# AbutmentScour

Comments:
The cross section at the bridge is deeper on the left side, which could indicate 1-2 ft of abutment scour, but the location of the pier also complicates the scour pattern and makes separating scour components difficult.  All scour was classified as contraction scour since the site was both horizontally and vertically contracted.


Comments:
The reference surface used to determine the depth of abutment scour was the concurrent ambient bed.  Therefore, the depth of abutment scour reported is additional local scour below the depth of contraction scour. Based on the cross sections from the bridge plans there appeared to be little contraction scour.  

Elevation of reference surfaces used:
4-4-97  1030
4-5-97  1029
4-9-97  1029

The rightmost pier may have had some influence on the depth of scour at the right abutment.  It is difficult to separate its effect from the abutment.  The abutment had the major effect and all scour is credited to the abutment with no scour reported for the pier.

The velocity reported for “at the abutment” is the maximum velocity observed in the area of the scour hole.  Note that the velocity dropped considerably at the right abutment as the scour hole depth increased causing an increase in the flow area.  The velocity at the left abutment held steady as did the depth and shape of the scour hole.


Comments:
The reference surface used to determine the depth of abutment scour was the concurrent ambient bed.  Therefore, the depth of abutment scour reported is additional local scour below the depth of contraction scour.  For this site, it appears that the scour holes may interact as there is only one or two depth measurement between the holes that define the ambient bed.

There was significant flow from the left upstream flood plain through the bridge opening.  This flow from the left flood plain significantly skewed the flow through the bridge opening, about 50 degrees on the average.  Refer to maps and sketches included in Other Detailed Data.

Measurements numbers 1 and 4 were made during a discharge measurement along the upstream face of the bridge.  The depths were measured with a sounding weight.  All other measurements were made using an echo sounded mounted on a knee-board.  The board was floated from upstream to downstream under the bridge.  The measurements reflect the depths at the upstream or downstream face of the bridge.

All hydraulic information is from the one discharge measurement.

The velocity at the abutments was much higher on 4/5/97:
  Left - 5.1 ft /sec
Right - 5.9 ft/sec

Embankment lengths were determined by projecting the measured water surface elevation onto the approach section from the BRW WSPRO model.


Comments:
The left upstream abutment was exposed to very high velocities coming out of the floodplain.  Intense boils and eddys were also present through the bridge opening at the left abutment.  The left abutment slope and adjacent pier (#2) both had scour protection (rip-rap), which most likely amplified the amount of scour in the channel at the left abutment.


Comments:
Substantial road overflow areas on both floodplains and dredge banks on both tops of banks preclude abutment scour.  No measurement or computations of abutment scour were made


Comments:
100-yr  Left Abutment
  Ae     Qe     Ve    a'      Ya     Fr     K1    Theta    K2     Ys
  28    133    4.75  8.0   3.49   .45   .55       70      .97    7.2 ft
Based on low values of hydraulic variables key to abutment scour calculations, and presence of riprap, abutment scour is believed to not be a factor.

500-yr  Left Abutment
  Ae     Qe     Ve     a'        Ya     Fr     K1    Theta    K2     Ys  
  23     87     3.78  5.0     4.60   .31   .55       70      .97    7.4 ft 
Based on low values of hydraulic variables key to abutment scour calculations, and presence of riprap, abutment scour is believed to not be a factor.


Comments:
100-yr Right Abutment
 Ae       Qe      Ve      a'        Ya     Fr     K1    Theta    
458     2155   4.71  128.6   3.56  .44   .55      62     
Because ratio of a'/Ya exceeds 25, use Eqn 25 from Hec-18 for right abutment scour - Ys=10.9
Adjust calculated scour for abutment scew from fig11, HEC-18,  theta=54, adustment=1.03    Ys=5.9 ft

500-yr Right Abutment
 Ae       Qe      Ve       a'      Ya     Fr     K1    Theta   
 621   2480   3.99   118.2  5.25  .31   .55        62     
Because ratio of a'/Ya exceeds 25, use Eqn 25 from Hec-18 for right abutment scour - Ys=14.2
Adjust calculated scour for abutment scew from fig11, HEC-18,  theta=62, adustment=.54    Ys=7.7 ft


Comments:
100-yr  Left Abutment
  Ae     Qe     Ve    a'      Ya     Fr     K1    Theta    K2     Ys
1603  6250  3.9   226  7.09   .26   .55       70      .97     23.7 ft
Because ratio of a'/Ya exceeds 25, use Eqn 25 from Hec-18 for left abutment scour - Ys=18.1ft
Adjust calculated scour for abutment scew from fig11, HEC-18,  theta=70, adustment=.91    Ys=16.5 ft

100-yr Right Abutment
 Ae       Qe      Ve     a'      Ya     Fr     K1    Theta    K2      Ys
3229  10302  3.19  541   5.97  .23   .55      110     1.03   27.6
Because ratio of a'/Ya exceeds 25, use Eqn 25 from Hec-18 for right abutment scour - Ys=14.7
Adjust calculated scour for abutment scew from fig11, HEC-18,  theta=110, adustment=1.03    Ys=15.1 ft

500-yr  Left Abutment
  Ae     Qe     Ve     a'        Ya     Fr     K1    Theta    K2     Ys
2016  7753  3.85 233.5  8.63   .23   .55       70      .97     26.2 ft
Because ratio of a'/Ya exceeds 25, use Eqn 25 from Hec-18 for left abutment scour - Ys=21.3ft
Adjust calculated scour for abutment scew from fig11, HEC-18,  theta=70, adustment=.91    Ys=19.4 ft

500-yr Right Abutment
 Ae       Qe      Ve       a'      Ya     Fr     K1    Theta    K2      Ys
4232  13954  3.30  548.7  7.71  .21   .55      110     1.03   31.5
Because ratio of a'/Ya exceeds 25, use Eqn 25 from Hec-18 for right abutment scour - Ys=18.4
Adjust calculated scour for abutment scew from fig11, HEC-18,  theta=110, adustment=1.03    Ys=19.0 ft


Comments:
Flow separation point on left valley wall was too far upstream to get a measurement and much of the floodplain flow re-entered the channel at a the section located one bridge-width upstream.  A section was made with the ADCP along the left bank of the channel to cut-off the floodplain flow entering the channel and gain insight to the amount of discharge that was being blocked by the roadway embankment.


Comments:
No measurement or computations of abutment scour were made at the Galvin Road overflow bridge.


Comments:
No evidence of abutment scour found during post-flood survey.

100-yr  Left Abutment
  Ae     Qe     Ve    a'      Ya     Fr     Ys
2509  1896  .76   470  5.34   .06    (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.

500-yr  Left Abutment
  Ae     Qe     Ve     a'        Ya     Fr      Ys
3027  2355  .78  470.5   6.43   .05    (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.


Comments:
100-yr Right Abutment
 Ae       Qe      Ve     a'      Ya     Fr     Ys
3077  2264   0.74  605   5.09   .06   (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.

500-yr Right Abutment
 Ae       Qe      Ve       a'      Ya     Fr    Ys
3742  2838   0.76   605.7  6.18  .05  (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.


Comments:
No evidence of abutment scour found during post-flood survey.

100-yr  Left Abutment
  Ae     Qe     Ve    a'      Ya     Fr     Ys
1973   940   .48   515  3.83   .04    (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.

500-yr  Left Abutment
  Ae     Qe     Ve     a'        Ya     Fr      Ys
2616  1174  .45  515       5.08   .04    (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.


Comments:
100-yr Right Abutment
 Ae       Qe      Ve     a'      Ya     Fr     Ys
2099  1030   0.49  527   3.98   .04   (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.

500-yr Right Abutment
 Ae       Qe      Ve       a'      Ya     Fr    Ys
2764  1266   0.46    527   5.24   .04   (*) ft
(*) - Because velocity and Froude number are relatively small, abutment scour is presumed to not occur.


# BedMat

Comments:
Only the D90=90 and D50=70 were reported with the data.  The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Only the D90=115 and D50=77 were reported with the data.The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Only the D90=13 and D50=1 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Only the D90=25 and D50=2.5 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Only the D90=6.5 and D50=1.5 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Only the D90=9 and D50=1 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778.  Only the D90=7 and D50=0.58 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778. Only the D90=8 and D50=1.1 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778. Only the D90=13 and D50=1.8 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778.  Only the D90=1.6 and D50=0.53 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778.  Only the D90=16 and D50=4 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778.  Only the D90=2.3 and D50=0.42 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778.  Only the D90=4.8 and D50=1.4 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
All bed-material samples were collected at the bridge.  Samples 1-3 are composites for the section.  Sample 4 was collected at station 700, sample 5 at station 760, sample 6 at station 800, sample 7 at station 700, and sample 8 at station 778.  Only the D90=5.4 and D50=1.6 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Photographs of the exposed streambed material at cross section 1 on April 22, 1969 were analyzed by the Zeiss method.  Photographs of some of the larger material near the right bank in cross section 1 showed large cobbles of 200 to 250 mm in diameter and a few boulders. Only the D90=130 and D50=90 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Only the D90=50 and D50=30 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16). Sediment sample number 1 was collected at the bridge near pier 4 using a drag sampler.  Sediment sample number 2 was collected in the approach section
upstream from the bridge and is thought to be more representative than sample number 1.


Comments:
Only the D90=58 and D50=14 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16). Sediment sample number 1 was collected at the bridge near pier 4 using a drag sampler.  Sediment sample number 2 was collected in the approach section
upstream from the bridge and is thought to be more representative than sample number 1.


Comments:
Sample collected 1000 ft upstream in the left half of the channel. Only the D90=0.28 and D50=0.18 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Sample collected 1000 ft upstream in the right half of the channel. Only the D90=16 and D50=9 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Sample collected 50 ft upstream from pier. Only the D90=21 and D50=15 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Streambed material particle sizes varied widely in samples collected along the cross section on the upstream side of the bridge.  The analyses of the surface samples collected upstram and between the piers showed that the D50 ranged between 0.1 mm and 9.8 mm.  No particular pattern in the distribution was observed, and a computed composite of all samples collected showed the average D50 to be about 3 mm.  The samples of fine material probably represented the material being transported in the standing waves.  The material which controlled the scour at the piers is that obtained in the samples containing the coarser materials.  Only the D90=23 and D50=7.6 were reported with the data. The D95, D84, and D16 were computed from the provided data.  The D84 was interpolated from the D90 and D50 using a log-probability interpolation.  Sigma was computed as D84/D50.  D95 and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95 or 16).


Comments:
Two bed-material samples collected on 6/25/90 are both five-sample
composites from the channel.  Sample 1 was taken 1000 feet upstream from
the bridge.  Sample 2 was taken 500 feet downstream from the bridge.


Comments:
Sample 1 was collected at station 870 with a BM-54.


Comments:
Sample 2 is a composite of samples collected with a BM-54 between stations
600-800.


Comments:
Sample 3 is a composite sample for the site collected with a clamshell.


Comments:
Sample 1 is a composite sample for the site, collected using a BM-54.


Comments:
Sample 2 was collected at station 555 using a clamshell sampler.


Comments:
Bed-Material Sample Numbers:
                 Left side      Center         Right side
Above bridge       8703          8704            8705
Below bridge       8706          8707            8708


Comments:
No bed-material samples were available for this site, so samples collected during the same event at Coushatta, located about 50 miles downstream, will be used.
Bed-Material Sample Numbers:
                 Left side      Center         Right side
Above bridge       8703          8704            8705
Below bridge       8706          8707            8708


Comments:
No bed-material samples were available for this site, so samples collected during the same event at Coushatta, located about 50 miles downstream, will be used.
                               
Bed-Material Sample Numbers:
                 Left side      Center         Right side
Above bridge       8703          8704            8705
Below bridge       8706          8707            8708


Comments:
No bed-material samples were available for this site, so samples collected during the same event at Coushatta, located about 50 miles downstream, will be used.
Bed-Material Sample Numbers:
                 Left side      Center         Right side
Above bridge       8703          8704            8705
Below bridge       8706          8707            87088


Comments:
On April 28, 1993, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected :
Cross    Distance
Section  Upstream  Sample   Comments
    1       8 ft     1     Bed at about mid-span between bents 16-17L.
    1       8 ft     2     Bed in vicinity of main piers 17-18L.
    2     400 ft     3     Mid-channel.
    2     400 ft     4     Left part channel.
    3     800 ft     5     Mid-to-left part of channel.
The right part of the channel bed at cross sections 2 & 3 seems to be
mostly silty clay. Bed sample no. 1 was used for bents 15-16L and sample
no. 2 was used for main piers 17-18L. For pile bents 12-14L, the material
is a clay with a cohesion of about 240 lb/ft2 and an angle of internal
friction of about 27 degrees, as determined from shear-strength tests on
Sept. 20, 1991.


Comments:
On April 28, 1993, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected :
Cross    Distance
Section  Upstream  Sample   Comments
    1     100 ft     1     Bed at about mid-span between bents 16-17L.
    1     100 ft     2     Bed in vicinity of main piers 17-18L.
    2     500 ft     3     Mid-channel.
    2     500 ft     4     Left part channel.
    3     900 ft     5     Mid-to-left part of channel. 
  The right part of the channel bed at cross sections 2 & 3 seems to be
mostly silty clay. Bed sample no.1 was used for bents 14-16R and sample
no.2 was used for main piers 17-18R. For pile bent 12-13R, the material
is a clay with a cohesion of about 240 lb/ft2 and an angle of internal
friction of about 27 degrees, as determined from shear-strength tests on
Sept.20, 1991.


Comments:
On November 18, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples:
Cross    Distance
Section  Upstream  Sample   Comments
    1       0 ft     1     Mostly gravel, some sand.
    2     300 ft     2     Mostly gravel.
    3     550 ft     3     Mostly sand.
From available bed samples, the bed material seems to be gap-graded,
indicating a mixture of uniform sand and uniform gravel. Bed sample no.1 was
considered most representative of the bed material at the base of pier Nos. 4-
6.


Comments:
On November 18, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples:Cross    Distance
Section  Upstream  Sample   Comments
    1       0 ft     1     Mostly gravel, some sand.
    2     300 ft     2     Mostly gravel.
    3     550 ft     3     Mostly sand.
From available bed samples, the bed material seems to be gap-graded,
indicating a mixture of uniform sand and uniform gravel. Bed sample no.1 was
considered most representative of the bed material at the base of pier Nos. 4-
6.


Comments:
On October 4-9, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected:
  Cross    Distance
Section  Upstream  Sample   Comments
    1     180 ft     1     Represents right part of chanel begin near station 8180.
    1     180 ft     2     Represents left part of channel end near station 8180. 
    2   1,200 ft     3     Within main flow of low-water channel, from tip of 4th 
                           jetty upstream to about 100 ft right.
    2   1,200 ft     4     Right part of channel, 175ft from tip of 4th jetty to RWE
    2   1,200 ft     5     Near upstream end of 4th jetty.
    3   2,100 ft     6     At upstream end of sand/gravel bar, all samples here
                           combined.  
   No bed samples were obtained at the piers due to debris, etc. Based on rod
probings at the piers, the material at the base of the piers is thought to be
mostly gravel with some sand and debris. Also, soil borings by the MDOT
indicate gravel. Therefore, bed sample no. 6 was selected as representative.


Comments:
On October 4-9, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected :
Cross    Distance
Section  Upstream  Sample   Comments
    1     100 ft     1     Represents right part of chanel begin near station 8180.
    1     100 ft     2     Represents left part of channel end near station 8180. 
    2   1,100 ft     3     Within main flow of low-water channel, from tip of 4th 
                           jetty upstream to about 100 ft right.
    2   1,100 ft     4     Right part of channel, 175ft from tip of 4th jetty to RWE
    2   1,100 ft     5     Near upstream end of 4th jetty.
    3   2,000 ft     6     At upstream end of sand/gravel bar, all samples here
                           combined.  
   No bed samples were obtained at the piers due to debris, etc. Based on rod
probings at the piers, the material at the base of the piers is thought to be
mostly gravel with some sand and debris. Also, soil borings by the MDOT
indicate gravel is present. Therefore, bed sample no. 6 is thought to be
most representative for the bed material at the base of pier nos. 4-6.
   The International Standard ISO 9195, "Liquid flow measurement in open
channels -Sampling and analysis of gravel-bed material", prepared by Technical
Committee ISO/TC 113 suggests sampling at the upstream end of gravel bars. The
coarse material is associated with the channel-forming processes and sediment^
transport. Therefore sample no. 6 was selected as the most representative.


Comments:
Diameters taken from a VA analysis of a grab sample from the bed at low flow under the downstream face of the bridge.
Results:
Size (mm)     4     5.6    8     11    16    23    32   45     64    90   128   180   
% < than    8.26 10.1 14.7 20.2 27.5 42.2 52.3 65.1 81.7 91.7  98.2  100


Comments:
Bed material sampling was done at locations where bed material was exposed and judged to be reasonably representative of streambed material and could be readily evaluated using simple equipment and techniques.  The particle-size distribution of the surface layer, obtained by a random particle count of the streambed, was used in the analysis because the surface-layer gradation was representative of the bed material in the channel reach.  The bed material is very mobile, and can be related to mounds of ball bearings.  The streambed configuration is highly variable from year to year.


Comments:
Pebble count started approx. 50 ft U/S of bridge, thru the bridge and to about 10' - 15' D/S of bridge. Efforts focused mainly around Pier1.  The surface layer is armored with coarse material and underlain by gravel and some sand.


Comments:
150 ft upstream of bridge in middle of the approach channel, 3 samples collected from boat during low-flow at depth ~ 5 ft.
Results:
Size (mm)     8     4     2      1     .5    .25   .125  .062       
% < than    100 100 100  99.8 95.6 16.3   0.5    .2


Comments:
No material collected under bridge, rocks and/or concrete present.  3 samples were collected from boat during low-flow just downstream of the bridge along the left bank at a depth ~ 4 ft.
Results:
Size (mm)     8      4     2      1    .5    .25  .125  .062  .016 .004  .002      
% < than    100 100 99.8 99.2 98.4 96.9 90.2  76.7  46.7 35.8  30.3


Comments:
150 ft downstream of bridge in middle of the exit section, 3 samples collected from boat during low-flow at depth ~ 27.5 ft.
Results:
Size (mm)     8     4     2      1     .5    .25   .125  .062  .016  .004  .002     
% < than    100 100 100  100  99.8 99.7  98.6  92.4  58.0  35.8  30.6


Comments:
3 samples collected in the scour hole at the upstream left abutment in the bridge opening at a depth ~ 24 ft.
Results:
Size (mm)     8     4     2      1     .5    .25    .125  .062  .016  .004  .002     
% < than    100 100 100  99.9  99.9 99.8  95.2  75.7  39.2  24.6  20.1


Comments:
3 samples collected in the scour hole in the upstream left bank scour hole at a depth ~ 12 ft.
Results:
Size (mm)     8     4     2      1     .5    .25    .125  .062  .016  .004  .002     
% < than    100 100 100  99.9  99.7 99.4  95.7  78.5  40.5  23.6  19.0


Comments:
Bed samples collected at the SR 35 bridge site in the main channel; gradation coefficient of 4.1


Comments:
This measurement was taken in the Zilpha Clay formation, which based on MDOT geotechnical reports in the area, the stream has very likely scoured down into or near the top of this formation during the floods of April 12, 1979, and the April 5, 2001. A 1997 MDOT geotechnical report for Yockanookany River at proposed State Highway 14 Bypass of Kosciusko, located about 1.9 mi northwest of this site, indicates that the top of the Zilpha formation possesses a cohesion of about 1,320 lb/ft3, a friction angle of 31 degrees, and a unit weight of 119 lb/ft3. Gradation tests suggest that the top of the formation has a D84 of about 0.37 mm, D50 of 0.16 mm, D16 of 0.026 mm, and a gradation coefficient of about 3.8. The 1941 test-pile reports at this site noted that soil borings indicated sand stone at elevation 377.0 ft, and indicated a significant increase in bearing capacity at about the same elevation. So, the top of the Zilpha formation is likely at about elevation 377 ft at this site.


Comments:
The bed material sample was collected from the downstream bridge face during low flow.  The material appears to consist mostly of medium to course sand mixed with some small shells and has the following grain size distribution:  
Size (mm)     8     4     2      1     .5    .25   .125  .062  .016  .004  .002       
% < than    100 97.1 91.5 76.7 51.9 23.4 18.2  13.2   5.9    4.8    4.3

There were no lithologic logs on the bridge plans in which to compare the samples.


Comments:
600 ft downstream from the bridges in the right third of the channel


Comments:
Upstream of bridge in left third of channel.


Comments:
Just upstream of bridge between piers 6 and 5. No documentation on size analysis but field notes indicate sand.


Comments:
Just upstream of bridge between piers 4 and 5. No documentation on size analysis but field notes indicate sand.


Comments:
Just upstream of bridge between piers 3 and 4. No documentation on size analysis but field notes indicate clay.


Comments:
From the soil logs for four test holes the bed material in the top layer consists of 6 to 10 feet of fine to medium sand underlain by 4 to 10 feet of coarser material, composed of 50% sand and 50% gravel up to 2.5-in size. No bed material samples were collected for the study.


Comments:
Bed-material samples were collected in a shallow area of the channel near
the bridge.  The sizes are based on 100 samples using the grid-sampling technique


Comments:
Bed-material samples were collected in a shallow area of the channel near
the bridge.  The D16, D50, and D84 were analyzed.  The D90 or D95 were not
analyzed because of the accuracy of the limited data set.


Comments:
The streambed is armored by gravel.  Bed-material samples were collected
in a shallow area of the channel near the bridge. The sizes are based on 100 samples using a grid-sampling technique


Comments:
The streambed is armored by gravel.  Bed-material samples were collected
in a shallow area of the channel near the bridge.  The D90 and D95 were not
analyzed because of the accuracy of the limited data set.


Comments:
Sizes based on 100 samples using the grid-sampling technique.


Comments:
Bed-material samples were collected in a shallow area of the channel near
the bridge.  Sizes based on 100 samples using the grid-sampling technique.


Comments:
Bed-material samples were collected in a shallow area of the channel near
the bridge.  The D16, D50, and D84 were analyzed.  The D90 or D95 were not
analyzed because of the accuracy of the limited data.


Comments:
Bed material samples were collected in a shallow area near the right bank.
Sizes based on 100 samples using the grid-sampling technique.


Comments:
Bed material samples were collected in a shallow area near the right bank.
The D16, D50, and D84 were analyzed, but the D90 and D95 were not analyzed
because of the accuracy of the limited data set.


Comments:
Bed-material samples were collected in a shallow area of the channel near
the bridge.  The D16, D50, and D84 were analyzed.  The D90 and D95 were not
analyzed because of the accuracy of the limited data set.


Comments:
Bridge-section composite sample, collected along the upstream bridge face.


Comments:
Sample collected at the upstream face of pier 1


Comments:
Sample collected at the upstream face of pier 2


Comments:
Sample collected at the upstream face of pier 3


Comments:
Sample collected at the upstream face of pier 4


Comments:
Sample collected at the upstream face of pier 1.


Comments:
Sample collected at the upstream face of pier 2.


Comments:
Sample collected at the upstream face of Pier 1.


Comments:
Sample collected at the upstream face of Pier 2.


Comments:
Sample collected 2 ft upstream of  the upstream face of Pier 1.


Comments:
Sample collected at the upstream face of Pier 2


Comments:
Sample collected 4 ft upstream of the upstream face of Pier 2


Comments:
Bed material sample # 43 (1978) collected 0.22 mile  upstream of bridge


Comments:
Bed material sample # 46 (1980) collected 0.28 mile downstream of bridge


Comments:
Sample collected at the upstream face of pier 3.


Comments:
Sample collected at the upstream face of pier 4.


Comments:
The bed material sample was collected from the upstream bridge face during low flow.  The material appears to be medium sand mixed with some small shells and has  the following grain size distribution:  
Size (mm)    16    8     4      2      1     .5     .25   .125  .062  .016  .004  .002       
% < than    100 67.4 64.8 61.1 56.7 45.4 20.8  13.1   7.9    3.3    2.4    1.9

There were no lithologic logs on the bridge plans in which to compare the samples.


Comments:
The samples were collected from the upstream bridge face and appeared consist of non-cohesive fine sandy/silt with the following grain size distribution:
Size (mm)    4     2      1     .5     .25   .125  .062  .016  .004  .002       
% < than    100 99.8 99.3 97.8 76.2  42.7  27.0  10.4   8.0    7.0 
The boring logs of the site have been included in the bridge plan profile.  Generally the logs indicate sand with some loam layers with fine gravel in the subbottom.


Comments:
D16 was less than 0.002
Bed-material samples were collected twice in the winter/spring of 1997.  The first samples were collected in February, when the discharge at Rosharon, Tex. was about 5,000 cfs.  All but two of the samples collected in March had median grain sizes in the clay-particle size range.  Additional samples were collected in April when the discharge at Rosharon, Tex. was about 45,000 cfs.  All but two of the April samples had median grain sizes in the sand-particle size range.  Values reported in the data base were subjective judgements of the typical value from the complete data presented below.

DATE    LOCATION      RANGE     D16        D50       D84      D95       Sigma
2/4/97   US1000       20-60    <0.002      0.041     0.18      0.29     4.3732
2/4/97   US1000      100-140    0.15       0.226     0.32      0.41     1.4779
2/4/97   US1000      180-260   <0.002      0.002     0.05      0.16    21.948
2/4/97   US1000       300      <0.002      0.003     0.13      2.16    47.879
2/4/97   US1000       340      <0.002      0.003     0.02      0.04     6.427
2/4/97   US30         25-130   <0.002      0.018     0.08      0.12     4.5676
2/4/97   US30        175-225   <0.002      0.003     0.14      0.19    54.243
2/4/97   US30        275-375   <0.002      0.002     0.06      0.20    24.773
2/4/97   US30         425      <0.002      0.003     0.03      0.06    12.913
2/4/97   DS600         20      <0.002      0.006     0.08      0.17    13.118
2/4/97   DS600         60      <0.002     <0.002     0.02      0.04
2/4/97   DS600       100-220    0.002     <0.002     0.02      0.05
2/4/97   DS600       260-340   <0.002     <0.002     0.03      0.09
Apr-97   US1000       0-45      0.07       0.139     0.20      0.26     1.7341
Apr-97   US1000        90       0.14       0.197     0.27      0.33     1.4138
Apr-97   US1000      135-18     0.13       0.193     0.28      0.37     1.4565
Apr-97   US1000      225-270    0.17       0.251     0.37      0.49     1.4843
Apr-97   US1000       315       0.18       0.393    10.65     17.95     7.7172
Apr-97   US1000       360       0.19       0.280     0.37      0.45     1.4133
Apr-97   US30        160-320    0.13       0.173     0.24      0.32     1.3796
Apr-97   US30         360       0.002      0.034      0.09     0.15     2.7418
Apr-97   US30         390      <0.002     <0.002      0.02     0.04
Apr-97   DS600        45-270    0.15       0.229      0.32     0.40     1.4644
Apr-97   DS600       315-360    0.14       0.20       0.28    19.80     1.3909


Lithologic logs from the bridge plans provided by the Texas Department of Transportation showed the streambed at FM 2004 to be composed of fine sand, silt, and clay.  Clay is the predominant material throughout the main channel below an elevation of about –50 ft MSL.  Above this elevation, clay was common but sands and silts were also noted.  This reach of river apparently moves significant amounts of sand from upstream during higher flows as noted in the April bed material samples, but clay appears to be the predominant bed material at the bridge.  During periods of low flow, sand is likely stored on the point bars located between Brazoria and FM 2004.


Comments:
No bed material samples were collected at this site. The boring logs show sand to be predominant.  Bed material samples size distributions presented in Holmes, R.R., Jr., 1993, Sediment transport in the lower Missouri and the central Mississippi Rivers, June 26 through September 14: U.S. Geological Survey Circular 1120-I were fairly consistent for samples at St. Louis, Missouri and at Chester, Illinois.  The bed material sizes reported herein were interpolated from this report.


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
400 ft from right bank
D50 was < 0.062


Comments:
No sieve information for bed material samples was available.  The low-water survey completed in July 1997 noted that the bottom was composed of firm rock and gravel and was uneven.  The bridge plans did not contain lithologic logs but did contain some penetration values, suggesting that there was no bed rock in the area.


Comments:
Bed-material size distribution reported are from information provided the MnDOT.  A review of the lithologic logs for the replacement bridge show that the subsurface material is primarily sands, silts, with some gravel.
D16 was less than 0.062


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
800 ft from right bank


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
1000 ft from right bank


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
1400 ft from right bank


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
average for day


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
200 ft from right bank


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
500 ft from right bank


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
700 ft from right bank


Comments:
Bed material samples were collected at the St. Louis gage by the USGS Missouri District.
1200 ft from right bank


Comments:
D16 was less than 0.002
See comments for US1000a.


Comments:
D50 was less than 0.002
See comments for US1000a.


Comments:
Sample collected at the upstream face of pier 5


Comments:
Sample collected at the upstream face of pier 6


Comments:
Sample collected at the upstream face of pier 7


Comments:
Sample collected at the upstream face of pier 8


Comments:
Sample collected at the upstream face of pier 27


Comments:
Sample collected at the upstream face of pier 28


Comments:
Sample collected at the upstream face of pier 29


Comments:
Sample collected at the upstream face of pier 30


Comments:
Composite sample from the approach section.


Comments:
Composite sample from the approach section


Comments:
Diameters taken from a VA analysis of a grab sample from the bed at low flow.
Results:
Size (mm)   1.00    0.500    0.250    0.125    0.062
% < than    100.0    85.1      34.5       1.7        0.8


Comments:
Diameters taken from VA analysis of a grab sample from the left overbank.
Results:
Size (mm)     1.00    0.500    0.250    0.125    0.062
% < than      100.0     98.0      94.1     65.9       34.3


Comments:
At upstream edge of bridge between piers 5 and 4 along left side of channel.


Comments:
In center of stream, 300 ft downstream from bridges.


Comments:
Diameters taken from a VA analysis of a grab sample from the bed at low flow under the upstream face of the bridge.
Results:
Size (mm)     4     5.6    8     11    16    23    32    45    64    90    128  180   
% < than    10.3 12.1 15.0 15.7 25.2 30.8 41.1 56.1 69.2  87.9  99.1 100


Comments:
Diameters taken from a VA analysis of a grab sample from the bed at low flow in the approach section.
Results:
Size (mm)     4     5.6    8     11    16    23    32   45     64    90   128   180   
% < than    11.3 13.4 14.8 22.5 25.4 35.2 51.4 63.4 79.6 91.5 97.2  100


Comments:
Diameters taken from a VA analysis of a grab sample from the bed at low flow upstream approx. 1/8 mile at campground/ Hannon fishing access.
Results:
Size (mm)     4     5.6    8     11    16    23    32    45     64    90    128   180   
% < than    6.80 8.74 11.7 14.6 24.3 30.1 38.8 54.4  68.9  88.3  99.0  100


Comments:
Diameters taken from a VA analysis of a grab sample from the bed at low flow near both sides of  pier #4.
Results:
Size (mm)     4   9.5   12.5   19   25   31.5   37.5   50   63
% < than     23   32     40   60    75      83     89     97  100


# Bridge

Description:
The structure is a prestressed girder bridge with 3 - 120' spans supported by two piers, both located in the main channel of the James River.  Pier #1 is on the left, looking downstream, and is supported by 13 concrete pilings.   Pier 2 is on the right and is also supported by 13 concrete pilings. The south and north abutments are each supported by 11 piles driven.  The bridge has a 2.897% downhill grade in the northbound direction.


Description:
The State Highway 35 crossing of Conehoma Creek consists of a 120-foot-long bridge near station 1642+58 (Bridge No. 153.1) with a span arrangement of 2 spans at 20 ft (feet), 1 span at 40 ft, and 2 spans at 20 ft. The bridge has 2 intermediate single-pile bents (nos. 2 & 5) and 2 intermediate double-pile bents (nos. 3 & 4). Both abutments are partially riprapped. Construction of the bridge was completed in 1941.


Description:
Two bridges are located at the site, bridge 539 and an older structure approximately 100 ft upstream. The bridge and piers are aligned relatively perpendicular to flow for both bridges.  The bridge is supported by sloping spillthrough abutments and two concrete webbed piers.  The foundations of the abutments and the two piers are supported by pilings driven to an elevation -14 ft MSL.


Description:
The Galvin Road Overflow bridge (structure #112) was constructed in 1993 and replaced a previous 530 ft long bridge at the same location.  The current bridge is 382 ft long and consists of ten composite glue-lam timber/concrete spans supported by 11 piers.  When the previous bridge was removed and replaced by the new shorter structure, the west approach fill was extended 146 feet and greatly increased the contraction of the floodplain flow path.  Piers 1 and 11 at the ends of the bridge are completely buried in the approach fills.  Piers 2 and 10 are intermediate piers.  The approach fills at the ends of the bridge are 15 to 20 ft high and block the floodplain.  The end slopes of both approach fills are sloped 1.5H to 1V and protected by riprap (D50 = 12 inches).


Description:
The structure is a high truss bridge with 3 - 150' spans supported by two piers, both located in the main channel of the Minnesota River.  Pier #1 is on the right, looking downstream, and is supported by 82 concrete pilings driven to depths ranging from 660.28' to 637.28'.  Pier #2 is supported by 82 concrete pilings driven to depths ranging from 665.96' and 654.96'.  The south and north abutments are supported by creosoted piles driven to 670.53' and 665.96', respectively.  The bridge has a 1% downhill grade in the northbound direction.


Description:
US 93 bridge is supported by one webbed pier (right pier looking downstream) and two piers consisting of 6 separate cylindrical piles located on the abutments.  The piers are numbered, beginning with the right pier (looking downstream).  The bridge spans the channel under low-flow conditions, with the  pier #2 located along the right edge of water and the left pier located on the left abutment.  The piers located on the abutments (#1 and #3) are protected with rip-rap.


Description:
This bridge is 1072 ft long and is supported by four piers spaced 250 feet apart.


Description:
The principal structure of this bridge is 1,500 ft long.  It is supported by six 6-ft-wide piers with pointed noses, spaced 250 ft apart.  A 500-ft approach on wooden pilings extends from the right bank to the bridge.  All piers are approximately aligned with the flow.


Description:
This bridge is 1500 ft long and crosses a channel of the Knik River at a 20 degree angle, 7.5 miles downstream from the scour site of the Knik River at Palmer, Alaska.  Its seven round-nose piers are spaced about 200 ft apart and are aligned with the flow.


Description:
The principal structure of this bridge consist of one 300-ft span and one 100-ft span, both supported by one large pointed-nose pier located in the right one third of the channel.  The pier is founded on two concrete-filled sheet-piling caissons 15 ft in diameter whose centers are aligned with the flow.


Description:
This bridge is 784 ft long and consists of one overhead-truss span 399 ft long
and four girder spans each about 95 ft long, supported by four round-nosed
concrete piers.  The piers, which taper from 2.5 ft wide at the cap to 5 ft
wide at the footing, are perpendicular to the roadway but are skewed to the
flow.  At high stages the angle of attack varies from 35-40 degrees.


Description:
This bridge consists of two 500-ft overhead-truss spans supported in the
center by a single pier.  At high flows the pier is approximately parallel
with the direction of the current at the water surface, but at low flows, the
pier is skewed at an angle of 10 degrees to the flow.  Not all of the flow of
the Tanana River passes beneath this main bridge because a bridged side
channel conveys water at high flows.


Description:
This bridge is of girder design consisting of seven spans supported by six
round-nosed pedestal-type piers 3.2 ft wide and spaced 92 ft apart, center to
center.  The total length of the bridge is 648 ft.  Two spur dikes, each 300
ft long, force the flow of the river to pass through the opening parallel to
the pier alignment.  The channel conveys the water during high flows.


Description:
The bridge, 1,604 ft long and 40 ft wide, is supported by 17 pile-bent
reinforced-concrete piers (includes abutment supports).   Each pile bent
consists of two concrete piles placed in drilled shafts spaced at
approximately 24 ft on center.  Four 7-ft-diameter bents (numbered 8-11
from the left bank, looking downstream) support spans over the main channel.
The overbank pile bents have 3.5-ft-diameter piles.   The four main-channel
bents, which have a solid, 1.5-ft-wide connecting web above grade between the
piles, are included in this database entry.   The pile-cap pedestals
support the bridge deck.


Description:
The bridge, 1294 ft long and 63 ft wide, is supported by eight reinforced-
concrete piers.   Piers 4 and 5, numbered from left abutment (looking
downstream), have scour measurements entered here.


Description:
The bridge, 1667 ft long and 46.8 ft wide, is supported by 13 reinforced-
concrete pile-bent piers.  Each bent consists of two piles spaced at
approximately 26 ft on centers with a pile-cap pedestal supporting the
bridge deck.  The abutments are pile bents with four piles.  Piers 7, 8,
and 10 (numbered from left bank when looking downstream), where scour
depths were estimated, have 9.8-ft-diameter (minimum) drilled-shaft piles.
Above grade, these piles taper to a 6-ft diameter.  A 1.5-ft web wall
extends between the piles at mid-level (elevation 212-238 ft).


Description:
This concrete slab and beam bridge is 663 ft long and it has 12 concrete piers (numbered left to right) spaced 51 ft apart with centerlines oriented at a 60-degree angle to the roadway centerline.


Description:
The bridge is 361 ft long, and it has eight concrete piers (numbered left
to right) spaced 40 ft apart with centerlines oriented perpendicular
to the bridge centerline.


Description:
Constructed in 1905, this 18-ft-wide one-lane bridge is 283 ft long, and it has three concrete-filled steel-cylinder piers (numbered left to right) spaced 105 ft apart with centerlines oriented perpendicular to the bridge centerline.
The middle spans are steel "through trusses", and the approach spans are
timber stringers. A 2.5-in asphalt pavement covers timber deck planks.
State inspections in 1984 indicated component of the spans are in fair to poor condition, and structural analysis indicated limited load-bearing capacity.
Undermining of the left approach fill and abutment, as well as possible
foundation failures at piers 1 and 2 were also indicated.  Consideration
of bridge closure or replacement was recommended.


Description:
The concrete bridge, built in 1972, is 176 ft long and 88.5 ft wide.
One concrete pier is located at the center of the channel.  The pier is
perpendicular to the bridge and is generally aligned with the channel.


Description:
The arched bridge, 547 ft long and 29 ft wide, has 12 pile-bent piers.  Three spans over the water, with possible four piers in the flow.  The bridge deck rests on the pile caps.  Each pile bent includes 5 piles spaced 6 ft apart on centers.  The piles in the center bents (C2 and C3) have a 3-ft-diameter concrete collar extending several ft above and below the waterline for protection from ice.  It is unlikely that the bridge would be overtopped.  Flow skew to the bridge (20 degrees maximum) varies during the tide cycle.


Description:
The bridge is 440 ft long and is supported by 10 pile bents spaced 40 ft
apart.  The piles extend from the silt and sand below the mud line, through
a concrete strut--located approximately at the high-water line--to pile caps
located just under the bridge structure.  (Pile bents J and K do not have
struts.)  Both abutments have riprap protection.


Description:
This is the upstream, southbound lane bridge of I-95.  The northbound lane
is parallel and is about 80 feet downstream.  The bridge has fenders between
piers 13 and 14.  These are supported by driven columns that also have local
scour associated with them.   The bridge deck is over 40 ft above the water
surface.  The bridge is skewed 20 degrees to flow, but piers are nearly
parallel to the flow.  There are actually 25 spans, but the BSDMS will only
accept 21 at most.  The main span is a three-span continuous steel girder
with maximum span length of 154 feet.  In the Edit>Site>Pier> section, piers
that are alike are listed under the same pier ID.  Piers that had scour data
(11,12,13) are identified separately.


Description:
Piers are numbered 1 through 3 with pier 1 closest to the left abutment
(looking downstream).  The abutments and piers are aligned perpendicular
to the bridge deck.


Description:
The left end of the bridge has a sloping abutment with levees upstream and
downstream.  The right end of the bridge has a modified sloping bank.
However, there are no real sloping embankments at either end of the bridge,
even though the bridge type is coded as Type III.
The piers are numbered 1 through 8, with pier 1 closest to the left abutment
(looking downstream).  The abutments and piers are skewed approximately 20
degrees right relative to the bridge deck.


Description:
This bridge has a sloping left abutment and embankment, but the right
abutment is a steep bank with rip rap.  The right end of the bridge is
high enough that it really does not have an embankment.  There are also
some levees/spoil banks on the right bank that would eliminate the effect
of sloping embankments.  The bridge type is coded as Type III, but both
abutments do not meet this criteria.
The piers are numbered 1 through 4, with pier 1 closest to the left abutment
(looking downstream).  The abutments and piers are skewed 10 degrees right
relative to the bridge deck.


Description:
This is the downstream bridge of two parallel bridges comprising the S.R.
3032 crossing of the Red River near Shreveport.  The bridge consists of 25
spans, 6 small piers on the right overbank, 6 larger piers from on the right
overbank through the main channel and onto the left overbank, and 12 small
piers on the left overbank.  Only the six large piers will be addressed in
this database entry.  The x-coordinate will be zero at the left abutment and
increase from left to right across the stream.  The y-coordinate will be zero
at the upstream face of the bridge and increase in the upstream direction.
The y-coordinate of the abutments were measured from a 1 inch = 100 ft
drawing.


Description:
This is the upstream bridge of two parallel bridges comprising the S.R. 3032
crossing of the Red River near Shreveport.  The bridge consists of 25 spans,
12 small piers on the left-overbank area, 6 larger piers from the left-
overbank area through the main channel to the right-overbank area, and 6
small piers on the right-overbank area.  Only the 6 large piers will be
addressed in this database entry.  The coordinate-system origin is located
at the upstream corner of the left abutment. The x-axis is along the upstream
face of the bridge with y increasing in the upstream direction.


Description:
The bridge is 155 ft long and has two 5-ft-wide piers on footers
spaced 53 ft apart.  The sharp-nosed piers and footers, skewed 30 degrees to
the bridge deck, are aligned with the flow at most stages.  The piers extend
2 ft upstream of the bridge at the nose but are square and flush with the
bridge at the tail end.


Description:
The bridge is 200 ft long and has three 4-ft-wide, 32-ft-long piers spaced
51 ft apart.  Each pier is a continuous web constructed on poured footers,
which probably extend down to bedrock.  The bridge has a constant slope from
the left bank (366.70 ft) to the right bank (357.86 ft).  The bridge has
flow-through abutments and should not be overtopped during high flow.
(Flow would possibly go over the roadway on the right bank.)


Description:
The bridge is 240 ft long and has four arch-supported spans.   Each pier,
formed by the the convergence of two arches, increases in width with
elevation from the 4-ft width at the base.  The face of each pier is flat.
The abutments are outside the arches on each end.  Plans are not available
for this structure.


Description:
The bridge is three-span prestressed concrete beams supported at two
intermediate spans by concrete piers on spread footings.  Abutments are
type-III spillthru with concrete abutment ends supported on spread footings.
Structural span measured from center of bearings of end bents equals 289 feet
per drawing. Span measured in the field pertaining to conveyance of bridge
section equals 288 feet.  Data describing piers, abutments, and other
longitudinal and vertical features are based on USGS survey work for measuring
on-site scour, to perform a level-2 analysis, and to perform beta-level
verification of the BRISTARS model using scour-related data from the
site (planned).


Description:
The bridge is a three-span concrete deck with two concrete piers providing
support between the two abutments.  Data describing piers, abutments, and
other longitudinal and vertical features are based on USGS survey work for
measuring on-site scour, to perform a level-2 analysis, and to perform
beta-level verification of the BRISTARS model using scour-related data from
the site (planned).  In the past 30 years, the bridge has been subjected to
three large floods having magnitudes of at least 85% of the 100-year peak
flow (Q100).  There is no evidence, however, of scour-induced foundation or
structural problems.  The bridge length described here is based on the
opening available for conveyance and may not agree with drawings.


Description:
Bridge is skewed 35 degrees to flow and consists of riveted plate
girders having four spans supported by three concrete tapered piers.
No flow angle of attack on piers was noted in the field.
Channel-geometry data are referenced to left edge of bridge opening.
Stationing of piers is based on site surveys for level-2 work and does
not relate to bridge-plan stationing.  Although flow impact to the
bridge was indicated to be straight, the presence of riprap on the
left bank and greater flow depth on left side of main channel indicate
that flow tends to impinge on the left side.


Description:
Bridge is perpendicular to flow and consists of a five-span concrete
deck with four concrete tapered piers providing support between the
two abutments.  Reference system for piers, abutments, and other
longitudinal features is based on USGS survey work used for level-2
analysis.  No flow angle of attack on piers was noted in the field.
Stationing of piers is based on site surveys for level-2 work and does
not relate to bridge-plan stationing.  Channel-geometry measurements
are not necessarily referenced from left edge of section thus,
comparison of sections currently requires reference to the pier
stationing data of this BSDMS file.


Description:
A major flood in 1972 undermined 5 of 6 piers.  Pilings prevented a bridge
collapse.  Crews placed material (streambed) around the piers after the
flood, but high flow in 1975 removed material.  Riprap was placed at the main-
channel piers in 1988.


Description:
The piers are recessed 5-10 ft under the bridge deck.  During the streamflow
measurements, it was not possible to sound directly upstream from the piers.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers.  The site plans are dated 1963.  The piers are
referenced from the left to right abutments when looking downstream.


Description:
Thebridge is constructed of concrete and steel I-beams, and has solid-
wall round-nose piers. The site plans are dated 1984. The piers are
referenced from the left the right abutments when looking downstream.


Description:
The bridge has a concrete deck on steel beam girders and solid-wall round-
nose concrete piers.  The channel was modified upstream and downstream
from the bridge during construction.  The site plans are dated 1951. The 
piers are referenced from the left to right when looking downstream.


Description:
The bridge has arched, steel I-beams with reinforced-concrete deck,
abutments, and piers.


Description:
The bridge was constructed of reinforced concrete and steel beams.  The site
plans are dated 1972, and it is assumed construction was completed in 1973.
The left abutment is a vertical wall with wingwalls that extend upstream and
downstream from the bridge. The right abutment is a sloping abutment with
spill-through-shaped embankments.


Description:
The bridge is of reinforced-concrete, steel-beam construction.
The site plans are dated 1933, and it is assumed construction was
completed in 1935.
Note: All bridge elevation data in this section was obtained from
the 1933 site plans, the msl datum was reported revised by 4.06 feet
in 1965.


Description:
The bridge is of reinforced-concrete, steel-beam construction.  The site
plans are dated 1934, and it is assumed that construction was completed
in 1935.  The bridge deck was renovated in 1992, but the piers and
foundations were not renovated.


Description:
The bridge has continuous steel beams with a reinforced-concrete deck
and substructure.  The site plans are dated 1972, and it is assumed
construction was completed in 1973.


Description:
The bridge, 282 ft long, has three 3-ft-wide piers constructed on pile footings spaced 81 ft apart.  The left end of the bridge is approximately 3 ft lower than the right end.  The piers are aligned with the flow at most stages.


Description:
The bridge is 250 ft long and has three 2.9-ft-wide, 32-ft-long piers on
wooden-pile foundations spaced 62 ft apart.  The piers are skewed 30 degrees
to the bridge.  The piers are slightly skewed to high flows (moving left to
right), which causes greater scour on the right side of the pier than on the
left side.


Description:
The westbound bridge is 187.5 ft long and is supported by four concrete
piers on pile caps and steel piles. The 2.5-ft-wide, 43-ft-long piers are
continuous webs and are spaced 37.5 ft apart. The roadway is elevated and
there are no side channels, therefore all flow is under the bridge.  There
are two bridges at this site.  The eastbound bridge (also two lanes but
older and narrower than the westbound bridge) is located 150 ft upstream
(approximately the width of the westbound bridge opening).  No measurements
were made at the eastbound bridge because of the narrow width and traffic
load.


Description:
The 360-ft-long, four-lane bridge has two concrete piers spaced 121 ft
apart.  Each pier, 3.17 ft wide and 83 ft long, is a continuous web its
entire length and is supported by pile footings. The bridge is very wide
and includes wide walkways on both sides and a wide median.  South Boston
Police close the bridge when high water inundates the the approach road
from the south.  Access to the bridge during floods is from the north. The
bridge will probably not be overtopped.


Description:
The bridge is 199 ft long and has three piers spaced 55 ft apart.
The piers, 2 ft wide and 41 ft long, are a continuous web of uniform width
supported by a footer keyed into undisturbed material.  The bridge is part
of a superelevated curve in the roadway, and the upstream side of the bridge
is lower than the downstream side.  The bridge is high above the streambed
and will probably not be overtopped.  The bridge has flow-through abutments
supported by piles.


Description:
The bridge, 210 ft long and 24 ft wide, is supported by three
concrete piers on pile foundations.  The piers are spaced 52 ft
apart.  The piers, 28-ft continuous webs resting on pile caps, taper
from 2.25 ft wide at the base to 1.5 ft wide at the top.  The piers are
numbered from right to left.


Description:
The bridge, 180 ft long, has two concrete piers spaced 70 ft apart.
The piers, continuous webs 2 ft wide and 30 ft long, are supported by
footers on bedrock.


Description:
The bridge, 208 ft long and 29 ft wide, has three concrete piers spaced
approximately 50 ft apart.  The three piers, 2 ft wide and 29.5 ft long,
are continuous webs supported by footers on bedrock.  The piers are aligned
with the flow at most stages. The abutments are supported by piles and are
protected by flow-through riprap aprons.


Description:
The SR 51/150 bridge is 2826 feet long.  Pile bents 1 through 8 and pier 9 are located on the Missouri bank; Piers 10, 11, and 12 are located in the main channel; Pier 13 is located at the edge of the main channel, Illinois side; and Pile bent 14 is located on the Illinois overbank.  The two spans from piers 10 to pier 12 are 670 feet each and are further supported by an overhead truss.  An underdeck truss runs between bent 8 and pier 10 and between pier 12 and bent 14.  The bridge was built around 1940 and was damaged by a tornado in 1944.


Description:
Concrete bridge supported by concrete piers on piles. Only pier 9 & 10 are in
the main channel. Top of pile caps for piers 9 & 10 approx elev initially, of
stream bed, at 673 ft NGVD. Pile caps are 16ft thick, extending down to 
657 ft under piers. Lowest part of bridge deck over channel at approx 
elev 744 ft. Bridge is perpindicular to channel.  Confinement of flood flows 
to width between levees on both banks results in high velocities at bridge. 
Abutments are behind levees and flow does not get near them. River banks 
under bridge are the levees and floodwalls which are continuous for 2.25 
miles US and 0.5 mile DS of bridge.  There is no contraction of flow width 
from approach to bridge, the only contraction in area is due to presence 
of the piers.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers. The site plans are dated 1934. The piers are
referenced from the left to the right abutments when looking downstream.
Note: Distances between centerlines and upstream / downstream pier faces are
approximate.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers. The site plans are dated 1931. The piers are
referenced from the left to right abutments when looking downstream.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall sharp-nose piers. The site plans are dated 1959. The piers are
referenced from the left to the right abutments when looking downstream.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers. The site plans are not dated. The piers are
referenced from the left to right abutments when looking downstream.


Description:
The bridge is constructed of concrete and steel I-beams. The bridge rests on
capped driven piles. The site plans are not dated. The piers are
referenced from the left to right abutments when looking downstream.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall sharp-nose piers. The site plans are dated 1941. The piers are
referenced from the left to right abutments when looking downstream


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers. The site plans are dated 1951 and consisted of plans
for only four piers. The bridge was later widened on the left overflow bank in
1962. The piers are referenced from the left to the right abutments when
looking downstream.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers. The site plans are dated 1978. The piers are referenced
from the left to right abutments when looking downstream.


Description:
This bridge is construced of concrete and steel I-beams, and it has solid-
wall round0nose piers. The site plans are dated 1941. The piers are referenced
numerically from the left to right abutments when looking downstream.


Description:
This bridge is constructed of concrete and steel I-beams, and it has solid-
wall round-nose piers. The site plans are dated 1958. All piers are referenced
numerically from the left to right abutments when looking downstream.


Description:
This bridge is a five span continuous concrete bridge resting on capped pile
substructures. The site plans are dated 1964. All piers are referenced from
the left to right abutments when looking downstream.


Description:
This bridge is constructed of concrete and steel I-beams, and has solid-wall
round-nose piers. Plas state constructed in 1953. All piers are
referenced from the left to right abutments when looking downstream.


Description:
The bridge was originally designed and constructed in the mid 1940s.  The original bridge had two twin-column piers located at the toe of the bank slopes.  The columns were hexagonal shaped, giving them a sharp upstream and downstream nose.  The foundations were poured footings with untreated timber piles beneath the footings.  The abutments had 45-degree wing walls both upstream and downstream.  In the early 1990s, the bridge was widened.  To accommodate the wider roadway a 20-inch round concrete-filled steel pile was placed upstream and downstream of each of the existing columns.  The upstream left column was reenforced with 6-inches of reenforced concrete from its base up to a level determined by the contractor in the field.  The abuments were widened and reinforced and new wing walls constructed.  The spill slopes at the abutments were graded to 2:1 on the left and 3.4 to 1 on the right.  The spill slopes were protected with grout to the waters edge at the time of construction, then large riprap was placed on the slope below the waterline.


Description:
The bridge is a relatively new bridge with wide shoulders and concrete guardrails.  The bridge is angled about 15 degrees to the low flow channel.  All cross sections collected during the flood were collected approximately parallel to the bridge deck.


Description:
The FM 2004 bridge over the Brazos River has 11 spans supported by pile bents.  The piers consist of three columns that extend from a footing to a bent cap, which supports the bridge deck.  The footings are located at the water-surface elevation or at the ground line and are supported by square concrete piles. The batter piles are exposed to drifting woody debris during normal flow conditions.

Pile bents 5, 6, 7, 8 consist of 22 1.5-ft square concrete piles located in 2 rows 5-ft apart on centerlines driven with a batter 24:1. The piles in each row are 4.25 ft apart on centerlines. A web wall extends from the top of the footing up 13 ft between the three columns.

Pile bents 2, 3, 4, 9, 10, 11 have 7.5 x 7.5 footings below each column.  Each footing is supported by 4 piles arranged in two rows with 4 ft between the centerlines of the rows.  These bents have no web walls.

Pier footing elevations for bents 2, 3, 4, 9, 10, 11 were estimated from a profile view.  Elevations for 5, 6, 7, 8 were provided on a drawing for proposed modifications to the foundations.  Pile tip elevations for 5, 6, 7, 8 were provided on a drawing for proposed modifications.  Pile tip elevations for 2, 3, 4, 9, 10, 11 were computed as the bottom footing elevation minus the pile length less 1 foot for embedment into the footing.


Description:
All of the piers were surveyed during the flood, but scour holes were only identified at piers 8 and 9.  Scans of the bridge plans have been included for piers 7 through 12.  Pier 12 is part of the navigation span and has a different design than piers 7 through 11.  Piers 7 through 11 are all similar in design, but the elevations of the various components of the piers are different. Each pier consists of two square caissons connected by a web wall near elevation 416 ft MSL.  The piers are tapered slightly in the direction of flow.  The caissons and web wall rest on a wider square-nosed pedestal, that rests on a wider square-nosed footing, that rests on a wider square-nosed seal, that is supported by H-piles.


Description:
The structural characteristics of the bridge are reported from rehabilitation plans provide by the Illinois Department of Transportation.  This is a truss bridge with 35 spans, however, only 3 spans comprise the section over the main channel of the Mississippi River.  Many of the spans are on the floodplain and behind levees.  

The piers have a complex shape.  The piers in the main channel consist of two columns above the flood elevation but are wall piers below the water.  The wall portions of the piers have three main portions: (1) an upper section which is sharp nosed and about 14 ft wide, (2) a middle section with is also sharp nosed and about 20 ft wide, and (3) a deep footing that rests on bed rock.


Description:
This bridge is a single-span structure with 45 degree wing-walls both upstream and downstream.  The bridge opening is smaller than both the upstream and downstream channel top widths.  The wing walls extend out to the width of the upstream and downstream channels.  The bridge and wing walls are aligned with the channel.


Description:
The bridge is an old truss bridge.  The bridge and its approach embankments are perpendicular to the main channel.  However, during the 1997 flood there was considerable skew as a significant amount of flow was coming from the left floodplain.  The flow through the bridge opening in the center of the channel was skewed about 50 degrees.


Description:
The bridge is constructed of concrete and steel I-beams, and it has solid-wall round-nose piers.  The site plans are dated 1964.  The piers are referenced from the left to the right abutments when looking downstream.


Description:
Structure L-344 consists of 60'-70'-70'-60' continuous I-beam spans supported by three dual-conical concrete column piers with partial web walls, and spill-through abutments. The piers and the abutments are founded on piling; the pier piling is driven to an elevation of 585-590 ft, and the abutment piling is driven to an elevation of 607 ft.


Description:
This is a relatively new bridge built in 1992. Maps from Delorme do not have the bridge in the correct (new) location. This site has two parallel bridges. Each bridge has six round-nose piers. The piers of the downstream bridge are located directly downstream of the piers on the upstream bridge. The piers are hammer-head type piers that are 18 ft long at the water surface and hammer-heads are 40 ft long. There was a rock dike (berm) about  100 ft upstream extending from the left abutment out the top of bank. Although the concrete portion of the abuments is not continuous between the bridges, there is only a short distance and shallow ditch between the two bridges, so the abutments have been treated for hydraulic purposes as if they were continuous abutments. The right abutment had a short guidebank on the upstream side.


Description:
Piers are numbered from left to right, #1 being the left-most line of piers (looking downstream) and #3 being the right-most line of piers.  There are three separate cyclindrical piers at each numbered line of piers, positioned at the upstream, centerline and downstream portion of the bridge.  Each of the nine piers are resting on 5.5 ft x 5.5 ft footers, which are supported by concrete piles.  The abutments are constructed with a 1.5:1 slope and are riprapped.


Description:
Piers are numbered from left to right, #1 being pile-bent on the left abutment and #5 being lpile-bent on the right abutment.  Piers #2 - #4 are located from left to right in the channel.


# Contact-Ref

Contact:
Steve Holnbeck
USGS, Montana District
(406) 457-5929
holnbeck@usgs.gov
or
Chad Wagner
USGS, Kentucky District
(502) 493-1912
cwagner@usgs.gov


Publication:
An unpublished level-2 analysis was performed by Montana USGS and is planned for submittal to MDT (March 2001) under the title: 
"Analysis of scour potentialfor bridge structure no. I00090292+04251 & 52 crossing Gallatin River at Interstate 90, four miles southeast of Manhattan, Montana".


Contact:
Dave Mueller 
USGS - Kentucky District
dmueller@usgs.gov
(502) 493-1935
or
Chad Wagner
USGS - North Carolina District
cwagner@usgs.gov
(919) 571-4021


Contact:
Dave Mueller 
USGS - Kentucky District
dmueller@usgs.gov
(502) 493-1935
or
Chad Wagner
USGS - Kentucky District
cwagner@usgs.gov
(502) 493-1912


Contact:
K. Van Wilson, Hydrologist, P.E.
U.S. Geological Survey
308 South Airport Road
Pearl, MS 39208-6649
Phone: (601) 933-2922
E-mail: kvwilson@usgs.gov


Contact:
Jeff Conaway, Hydrologist
U.S. Geological Survey Water Resources Division
4230 University Drive, Suite 201
Anchorage, Alaska 99508-4664
(907)-786-7041
jconaway@usgs.gov

Publication:
An unpublished level-2 analysis was performed by Alaska USGS under the title: 
"Bridge no. 539
Knik River, Old Glenn Highway
Step-Backwater Model and 
Bridge Scour Analysis"


Contact:
Chad Wagner
USGS - North Carolina District
cwagner@usgs.gov
(919) 571-4021
or
Rod Lakey, Senior Engineer
Lewis County Department of Public Works
350 N. Market Boulevard
Chehalis, WA 98532
(360) 740-1123


Publication:
Analysis of Scour Potential for Bridge Structure No. S00370 000+0.5361 Crossing Bitterroot River at Secondary Route 370, 2 Miles Northeast of Victor, Montana

WRD, US Geological Survey, Helena, MT in cooperation with the Montana Department of Transportation

June- 1999


Contact:
Steve Holnbeck
USGS, Montana District
(406) 457-5929
holnbeck@usgs.gov
or
Chad Wagner
USGS, North Carolina District
(919) 571-4021
cwagner@usgs.gov

Publication:
An unpublished level-2 analysis was performed by Montana USGS and is planned for submittal to MDT (January - 1994) under the title: 
"Analysis of Scour Potential for Bridge Structure No. P00001491+08241 Beaver Creek Overflow 7 Miles West of Saco, MT"

January - 1994


Contact:
U.S. Geological Survey, Water Resources Division
218 E Street, Skyline Building
Anchorage, AK  99501

Publication:
U.S. Geological Survey
Water-Resources Investigations 32-75 
Scour at Selected Bridge Sites in Alaska
By Vernon W. Norman
November 1975


Publication:
U.S. Geological Survey
Water-Resources Investigations 32-75
Scour at Selected Bridge Sites in Alaska
By Vernon W. Norman
November 1975


Publication:
U.S. Geological Survey
Water-Resources Investigations 32-75
Scour at Selected Sites in Alaska
By Vernon W. Norman
November 1975


Contact:
U.S. Geological Survey, Arkansas District
2301 Federal Office Building
700 West capitol Bldg.
Little Rock, Ark. 72201

Publication:
U.S. Geological Survey
Water Resources Investigations Report 92-4126
"Scour around bridge piers on streams in Arkansas"
by Rodney E. Southard


Contact:
U.S. Geological Survey - Arkansas District
2301 Federal Office Building
700 West Capitol Bldg.
Little Rock, Ark. 72201

Publication:
U.S. Geological Survey
Water Resources Investigations Report 92-4126
"Scour around bridge piers on streams in Arkansas"
by Rodney Southard


Contact:
U.S. Geological Survey, Arkansas District
2301 Federal Office Building
700 West Capitol Bldg.
Little Rock, Ark. 72201

Publication:
U.S. Geological Survey
Water Resources Investigations Report
"Scour around bridge piers on streams in Arkansas"
by Rodney Southard


Contact:
Robert D. Jarrett, Hydrologist
U.S. Geological Survey, Water Resources Division, Colorado District
Building 53, Denver Federal Center, Mail Stop 415,Box 25046 
Denver, CO 80225

Publication:
U.S. Geological Survey
Water Resources Investigations Report 86-4030
Pilot Study for Collection of Bridge-Scour Data
by Robert D. Jarrett and Jeanne M. Boyle


Contact:
Robert D. Jarret, Hydrologist
U.S. Geological Survey, Water Resources Division, Colorado District
Building 53, Denver Federal Center, Mail Stop 415, Box 25046
Denver, CO 80225

Publication:
U.S. Geological Survey
Water Resources Investigations Report 86-4030
Pilot Study for Collection of Bridge-Scour Data
by Robert D. Jarret and Jeanne M. Boyle


Contact:
USGS
3600 West Broad Street  Suite 606
Richmond, VA  23230
(804) 771-2427

Publication:
Hayes, Donald C., 1993, Site Selection and Collection
     of Bridge-Scour Data in Delaware, Maryland, and
     Virginia:  U.S. Geological Survey Water-Resources
      Investigations Report 93-4017, 23 p.


Publication:
Hayes, Donald C., 1993, Site Selection and Collection of Bridge-Scour Data in Delaware, Maryland, and Virginia:  U.S. Geological Survey Water-Resources Investigations Report 93-4017, 23 p.


Contact:
Landers, Mark.  Hydrologist, Office of Surface Water, USGS National Center,
12201 Sunrise Valley Drive, Mail Stop 415, Reston, VA  22092.
Ph. (703) 648-5977.


Contact:
Robert L. Miller or John T. Wilson
U.S.G.S. - W.R.D.
5957 Lakeside Boulevard
Indianapolis, IN  46278    (317) 290-3333


Contact:
Robert L. Miller or John T. Wilson
U.S.G.S.-W.R.D.
5957 Lakeside Boulevard
Indianapolis, IN  46112   (317) 290-3333


Contact:
Robert L. Miller or John T. Wilson
U.S.G.S.-W.R.D.
5957 Lakeside Boulevard
Indianapolis, IN  46278  (317) 290-3333


Contact:
Mark N. Landers
U.S. Geological Survey, National Center
12201 Sunrise Valley Dr., Mail Stop 415
Reston, VA  22092                            Phone:  (703) 648-5977


Contact:
Mark N. Landers
U.S. Geological Survey, 
National Center
12201 Sunrise Valley Dr., 
Mail Stop 415
Reston, VA 22092
Phone:  (703) 648-5977


Contact:
U.S. Geological Survey, WRD, MS. District
100 W. Capitol Street, Suite 710
Jackson, MS. 39269

Publication:
Turnipseed, D.P., and Smith, J.A., 1992, Monitoring
     lateral movement of channel banks on the Pearl
     River in Mississippi: Mississippi Water Resources
     Conference Proceedings, 1992, p.101-108.


Contact:
U.S. Geological Survey, WRD, MS. District
100 W. Capitol Street, Suite 710
Jackson, MS. 39269
(601) 965-4600

Publication:
Hopkins, G.R., Vance, R.W., and Kasraie, B., 1975, Scour around bridge piers, Federal Highway Administration Report No. FHWA-RD-75-56,205 p.----, 1980, Scour around bridge piers, Federal Highway Administration Report No. FHWA-RD-79-103, 141 p.


Publication:
Turnipseed, D.P., and Smith, J.A., 1992, Monitoring lateral movement of channel banks on the Pearl River in Mississippi: Mississippi Water Resources Conference Proceedings, 1992, p.101-108.


Contact:
Stephen R. Holnbeck or Chuck Parrett (406)449-5263
U.S. Geological Survey
301 South Park Ave., Fed. Bldg. Rm 428
Helena, MT 59626

Publication:
An unpublished level-2 analysis, to be submitted to MDT, will be on file at USGS - Montana District in late-January 1994.


Contact:
Stephen R. Holnbeck or Charles Parrett (406)449-5263
U.S. Geological Survey
301 South Park Ave., Fed. Bldg. Rm 428
Helena, MT 59626

Publication:
An unpublished level-2 analysis was performed by USGS and submitted to MDT (April 1992) under the title: "Analysis of scour potential for bridge structure no. P00050070+04611 Gallatin River 5M S Gallatin Gateway, MT".


Contact:
Steve Holnbeck
USGS, Montana District
(406) 457-5929
holnbeck@usgs.gov
or
Charles Parrett 
U.S. Geological Survey, Montant District
(502) 457-5928

Publication:
An unpublished level-2 analysis was performed by USGS and is planned for submittal to MDT (February 1994) under the title: "Analysis of scour potential
for bridge structure no. P00011020+04171 Yellowstone River 11M SW Emigrant, MT".


Publication:
An unpublished level-2 analysis was performed by USGS and submitted (March 1993) under the title: "Analysis of scour potential for bridge structure no. P00003096+05771 Badger Cr 15 M SE Browning, MT".


Contact:
Pete Riehlman, NYSDOT, Region 3 hydraulic engineer (315) 428-4715.


Contact:
Craig Mozrall, NYSDOT hydraulic engineer, Region 6 (607) 324-7580


Contact:
Mike Ferrel. NYSDOT Region 9, (607) 771-5467


Contact:
Mike Ferrel, NYSDOT Region 9, (607) 771-5467.


Contact:
Terry LaFrance, NYSDOT, Region 4 (716) 272-3383.


Contact:
Tom Soya, Pennsylvania Department of Transportation (PENNDOT),
Bridge inspection coordinator (717) 963-3078.


Contact:
Scott Jackson  
U.S. Geological Survey 
614-469-5553  
75 West Third Ave. 
Columbus, Ohio 43212
or
William Krouse 
Ohio Department of Transportation
614-466-2398
25 South Front St.  
Columbus, Ohio 43216

Publication:
Jackson, K.S., 1996, Evaluation of bridge-scour data at selected sites in Ohio: U.S. Geological Survey Water-Resources Investigations Report 97-4182.


Publication:
Hayes, Donald C., 1993, Site Selection and Collection of Bridge-Scour Data in Delaware, Maryland, 
and Virginia:  
U.S. Geological Survey 
Water-Resources Investigations Report 93-4017, 23 p.


Contact:
David S. Mueller
U.S. Geological Survey
9818 Bluegrass Parkway
Louisville, KY 40299

Publication:
Mueller, D.S., Landers, M.N., and Fischer, E.E., 1995, Scour measurements at bridge sites during the 1993 upper Mississippi River basin flood: Transportation Research Record, no. 1483, p. 47-55.


Contact:
George H. Carlson
(612) 783-3220
USGS-WRD 
2280 Woodale Drive
Mounds View, MN  55112-4900
or
Scott Jackson
(614) 469-5553
USGS-WRD 
975 W. 3rd Avenue
Columbus, OH  43212


Contact:
David Mueller
U.S. Geological Survey
9818 Bluegrass Parkway
Louisville, KY  40299

Publication:
Mueller, D.S., and Hitchcock, H.A., 1998, Scour measurements at contracted highway crossings in Minnesota, 1997:  ASCE, Water Resources Engineering ’98, Memphis, TN, p. 210-215.


Publication:
Mueller, D.S., and Parola, A.C., 1998, Detailed scour measurements around a debris accumulation:  ASCE, Water Resources Engineering ’98, Memphis, TN, p. 234-239.

Parola, A.C., Kamojjala, S., Richardson, J.E., and Kirby, M.W., 1998, Numerical Simulation of Flow Patterns at a Bridge with Debris:  ASCE, Water Resources Engineering ’98, Memphis, TN, p. 240-245.


Publication:
Mueller, D.S., Landers, M.N., and Fischer, E.F., 1995, Scour measurements at bridge sites during 1993 Upper Mississippi River Basin flood: Transportation Research Record 1483, p. 47-55.

Foster, J.E., 1988, Jefferson Barracks Brige movable-bed model study: U.S. Army Corpse of Engineers Waterways Experiment Station Miscellaneous Paper HL-88-7.


Publication:
Mueller, D.S., Landers, M.N., and Fischer, E.F., 1995, Scour measurements at bridge sites during 1993 Upper Mississippi River Basin flood: Transportation Research Record 1483, p. 47-55.


Contact:
Richard J. Huizinga
1400 Independence Road, MS 200
Rolla, MO 65401
(573) 308-3570


Contact:
Dave Clamon
Hydraulic Engineer, Iowa DOT
(515) 239-1487
or
Dave Mueller
Hydrologist, USGS
(502) 493-1935


Publication:
An unpublished level-2 analysis was performed by Montana USGS and is planned for submittal to MDT (January 1994) under the title: 
"Analysis of Scour Potential for Bridge Structure No. P00001490+05771 Beaver Creek Overflow and Stock 9 Miles West of Saco, MT"


# ContractionScour

Comments:
The data for the contracted section were measured from the bridge deck during the flood event on the specified date.  The geometry of the reference uncontracted section was measured during low flow.  The hydraulic data for the uncontracted section were estimated using WSPRO to estimate the approach hydraulics for the reference channel geometry and the flood discharge observed on the date of the contracted section measurement.


Comments:
Scour at CR14 was measured on 4-4-97 and 4-5-97.   The left approach was overtopped, with significant flow.  Due to weather and site conditions the overflow could not be measured. The bridge substructure was partially submerged on 4-4-97, but the upper low-chord was still above the water surface.  The fall through the bridge on 4-4-97 was 0.42 ft.  On 4-5-97 the entire substructure was submerged both upstream and downstream and the water surface upstream and downstream was essentially the same. Discharge through the bridge, but not over the roadway, was measured on 4-5-97 and thus only scour data from 4-5-97 are reported.  

The cross sections collected on 4-4-97, 4-5-97, and 7-16-97 were compared.  The downstream cross sections showed good agreement among all the measurements.  Upstream the 4-4-97 and 4-5-97 measurements again showed reasonable agreement.  However, the measurements made on 7-16-97 were more difficult to interpret.  The left side of the upstream cross sections always reflected a location near the bridge because access to the upstream left bank was hindered by the oxbow lake.  Thus the cross sections at 75 and 100 ft upstream collected on 7-16-97 are actually only about 25 ft upstream on the left bank.  The left side of these cross sections displays scour.  It could not be determined from the data if this was a remnant of the old channel or if the scour that developed under the bridge during the flood, extended some ways upstream.  Due to the uncertainty in the upstream cross sections and the consistency of the downstream cross sections, the cross section approximately 90 ft downstream collected on 4-5-97 was used as the reference surface for determining the depth of scour.

The average depth of contraction scour (3.9 ft) was determined from the difference in average elevation of the active channel bottom using the cross sections 90 ft downstream and along the upstream edge of the bridge collected on 4-5-97.  Nearly 5 ft of elevation difference was observed from the downstream section to the deepest portion of the cross section collected along the upstream edge of the bridge.  Due to the lack of access under the bridge, it is not know if the measured scour is the maximum scour at the site.

No hydraulic measurements are available in the approach or exit sections of the channel.

According the hydraulic analysis provided by Chippewa County the mean velocity through bridge at the overtopping flood of 17,500 cfs would be 6.3 ft/sec.  On 4-5-97 only 11,800 cfs was measured going through the bridge with a mean velocity of 3.6 ft/sec and a maximum point velocity of 5 ft/sec.


Comments:
No hydraulic measurements were made on this date.  However, from the channel geometry measurements no contraction scour was observed.


Comments:
There was no apparent scour at the bridge, either abutment or contraction scour, despite the contraction present at the bridge.  However, there was a scoured area about a channel width downstream from the bridge.  This could have been caused by the flow contracted through the bridge opening, which may have reached a maximum contraction downstream from the bridge.  This however, was not the flow pattern observed on 4-8-97.  The configuration of this scour hole and the channel upstream and downstream from the bridge was nearly identical on 4-8-97 and in July 1997.

The contraction scour reference surface was determined by computing the average bottom elevation of the each cross section collected on 4-8-97.  The scour area was located between 55 and 70 ft downstream.  Thus the sections near the hole were not used in the average.  The average elevation was about 1114.7 ft MSL.  The minimum average bottom elevation of a cross section was 1113.2 ft MSL.  Thus, the depth of scour was 1.5 ft.  Due to the variability of streambed elevation the accuracy is only about 1 ft, with the majority of the error attributed to determining the reference surface.  A thalweg profile also showed a scour 1.5 ft.

There was about 0.1 ft of fall through the bridge on 4-8-97.

Analysis of  cross sections collected on 4-8-97

Location          Avg. Bot. Elev.          Bottom width          Top width
US 113             1114.95                     30                    55
US 78              1114.75                     24                    56
US 52              1114.5                      30                    50
US 24              1114.26                     29                    37
US 15              1114.83                     20                    35
DS 15              1115.29                     18                    35
DS 55              1113.86                     30                    60
DS 70              1113.16                     --                    70
DS 115             1115.6                      --                    67

The typical bottom widths for the upstream and bridge opening are reported as the uncontracted and contracted widths.  The average velocity in the contracted section is the average velocity in the bridge opening.  No other criteria are reported due to the unusual configuration of the scour and the possibility that the scour hole could be a result of something other than the bridge contraction.


Comments:
Contraction scour was computed as the difference in average bed elevation between uncontracted and contracted sections, adjusted for bed slope.  

The appropriate reference surface was determined from an analysis of cross sections collected by BRW on 6/5/95 and the USGS during the flood on 4/5/97.  Cross sections on these two dates collected approximately 300 ft upstream from the bridge show only about 0.5 difference the channel bottom elevation. The flood section was the lower of the two.  Downstream from the bridge the cross section surveyed on 6/5/95 (approximately 75 ft downstream) and the cross section surveyed on 4/5/97 (approximately 200 ft downstream) are similar, with less than 1 ft in variation in the channel bottom elevations.  The 4/5/97 cross section 100 ft downstream was about 1.5 below the 6/5/97 cross section at 75 ft downstream.  It was assumed that the 4/5/97 cross section could have been effected by the scour at the bridge section. Thus, it was not considered in the setting of the reference surface.  The WSPRO bridge section surveyed by BRW on 6/5/95 showed from 1 to 2 ft of abutment scour in the cross-section.  However, the center of the channel at the bridge appears to be representative of consistent channel slope from the upstream section to the downstream section.  Since little general scour was observed at the upstream and downstream sections the mean elevation of the unscoured portion of the WSPRO bridge section will be used as the contraction scour reference surface, elevation 981.5 ft.

The contracted section on 4/5/97 was measured under the bridge from data collected by an acoustic Doppler current profiler.  The depths represent a weighted average of the four beam depths.  Because a weighted-average was used it is possible that the local abutment scour was not detected.  The maximum lowering of the stream bed was actually 7.5 ft, however, when the entire bed below the bridge was averaged the depth of contraction scour was only 3.1 ft.  The hydraulic data presented for measurement number 1 were collected with the ADCP.  The ADCP data showed many missing ensembles that were estimated in the final processing.  There was not clear delineation of the channel banks in the approach section, creating a degree of uncertainty in the approach discharge.  Overall it is expected that the approach discharge is +/- 20% and the total discharge is +/- 10%.

Measurements number 2 was made during a discharge measurement along the upstream face of the bridge.  The depths were measured with a sounding weight.  Measurements 3 and 4 were made using an echo sounded mounted on a knee-board.  The board was floated from upstream to downstream under the bridge.  The measurements reflect the depths at the upstream or downstream face of the bridge.

The cross sections measured on 4/9/97 all showed a similar pattern with abutment scour holes on each side and a sharp mound in between the scour holes but skewed towards the left bank.  It appears that the abutment scour holes may have overlapped.  The highest elevation in the center of the cross section was subtracted from the reference surface to obtain the depth of contraction scour.  No data in the approach section was collected on 4/9/97.


Comments:
Contraction scour was computed as the difference in average bed elevation between uncontracted and contracted sections, adjusted for bed slope.  

Based on the elevation of the main channel between the abutment scour holes there appears to be only 1 ft or less of contraction scour and therefore a value of zero contraction scour is reported.  No measurements in the uncontracted sections could be made.  However, comparisons of the center of the contracted section with the cross section on the bridge plans collected in 1991 showed not change in elevation except in the areas effected by local scour.  Thus, a zero contraction scour was reported.

The average depth and velocity of the contracted section were computed from the discharge measurements.  The average depth included the abutment scour holes.


Comments:
Contraction scour was computed as the difference in average bed elevation between uncontracted and contracted sections, adjusted for bed slope.  

Based on the elevation of the main channel between the abutment scour holes there appears to be only 1 ft or less of contraction scour and therefore a value of zero contraction scour is reported.  No measurements in the uncontracted sections could be made.

The average depth and velocity of the contracted section were computed from the discharge measurements.  The average depth included the abutment scour holes.


Comments:
These values represent WSPRO model computed contraction scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data).   The computed pier scour was 15.3 feet, for a total scour of 16.5 feet.  The actual measured total scour on this date was 17.2 feet (from measurement notes).  The engineer decided not to attempt to separate the total scour measurement into components due to the complexity that was introduced by the large debris raft at the pier.


Comments:
These values represent computed contraction scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data).   The computed pier scour was 17.1 feet, for a total scour of 17.1 feet.  The actual measured total scour on this date was 17.1 feet (from measurement notes).  The engineer decided not to attempt to separate the total scour measurement into components due to the complexity that was introduced by the large debris raft at the pier.


Comments:
These values represent computed contraction scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data).   The computed pier scour was 19.2 feet, for a total scour of 19.2 feet.  The actual measured total scour on this date was 20.0 feet (from measurement notes).  The engineer decided not to attempt to separate the total scour measurement into components due to the complexity that was introduced by the large debris raft at the pier.


Comments:
These values represent computed contraction scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data).   The computed pier scour was 21.1 feet, for a total scour of 21.5 feet.  The actual measured total scour on this date was 20.0 feet (from measurement notes).  The engineer decided not to attempt to separate the total scour measurement into components due to the complexity that was introduced by the large debris raft at the pier.


Comments:
These values represent computed contraction scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data).   The computed pier scour was 12.8 feet, for a total scour of 12.8 feet.  The actual measured total scour on this date was 11.8 feet (from measurement notes).  The engineer decided not to attempt to separate the total scour measurement into components due to the complexity that was introduced by the large debris raft at the pier.


Comments:
A few logs were jamed perpendicular to the flow along the nose of pier #1. The deepest area of scour through the bridge reach was observed to be downstream of the bridge on the left side of the channel (between the left abutment and pier #2).  The riprap protection on the abutments and piers greatly diminished scour through the bridge and focused the contracted flow energy beyond the bridge and the protected areas, resulting in the deep scour hole downstream of the bridge (see measurement 2).                                          Detailed data of the bridge reach was collected during the flood with a manned boat and ADCP.  Inspection of the "approach" section (one bridge width upstream) revealed a large discharge relative to that of the contracted opening and a bed elevation similar to the contracted section.  It was discovered that the upstream bend forced a majority of the left floodplain flow back into the main channel before the "approach" section.  A cross section made further upstream showed much less discharge, which was consistent with channel discharge downstream of the bridge opening, and an average channel elevation ~ 15 higher than contracted section.The widths and corresponding hydraulic characteristics for the uncontracted sections are representative of the portion of the channel in which live-bed transport would be expected.


Comments:
Contraction scour estimated from comparing real-time upstream bridge face bed elevation during June, 1997 flood with baseline upstream bridge face bed elevation surveyed on 9/23/92.


Comments:
Contraction scour estimated from comparing real-time upstream bridge face bed elevation during June, 1996 flood with baseline upstream bridge face bed elevation surveyed on 9/23/92.


Comments:
Detailed data of the bridge reach was collected during the flood with a manned boat and ADCP.  Inspection of the "approach" section (one bridge width upstream) revealed a large discharge relative to that of the contracted opening.  It was discovered that the blockage caused by the roadway embankment forced a majority of the left floodplain flow back into the main channel at the "approach" section.  A cross section made further upstream showed much less discharge, which was consistent with channel discharge downstream of the bridge opening.  Data from an ADCP section that cut-off the left floodplain flow accounted for all but 500 cfs of the difference in discharge between the "approach" section and the section further upstream.  The section furthest upstream was used as the uncontracted section because it was most representative of the flow naturally carried by the main channel had the roadway embankment not be present.  The widths and corresponding hydraulic characteristics for both the contracted and uncontracted sections are representative of the portion of the channel in which live-bed transport would be expected.


Comments:
Remanents of the old bridge appear to be influencing the bathmetry of the bridge section, where the upstream bridge face section is 3-4 feet higher than the downstream bridge face section as well as other section collected further upstream of the bridge.  It would also explain the inability to collect bed material samples at the upstream bridge face.


Comments:
Left overbank scour measurement.                                                         Contraction scour was estimated for the floods of April 12, 1979, and April 5, 2001, and compared to measured scour. Since the measured scour was based on a post-flood sections, infilling could possibly suggest measured scour depths less than what actually occurred.  Contraction scour characteristics included in the database were taken from the WSPRO model.
The HEC-18 estimated post-scour elevations suggest that the bridge would have collapsed during both the 1979 and 2001 floods because the piling would have been undermined. Keeping the same subarea stationing limits for the post-scour section as were used for the pre-scour section so that a consistent top width could be determined, the average depths for pre- and post-scour conditions were determined for the overbank and the main channel. These pre- and post-scour depths were used to determine average contraction (mostly) scour depths in the overbank and main-channel areas.               
April 12, 1979:  HEC-18 method suggested about 3, 19, and 3 ft of contraction scour in the left (south) overbank, main channel, and right (north) overbank, respectively. HEC-18 method for pressure-flow conditions suggested about 2, 27, and 0 ft of contraction scour in the left (south) overbank, main channel, and right (north) overbank, respectively.


Comments:
Contraction scour was estimated for the floods of April 12, 1979, and April 5, 2001, and compared to measured scour. Since the measured scour was based on a post-flood sections, infilling could possibly suggest measured scour depths less than what actually occurred.  The only approach cross-section data available for the site was surveyed just after the 1979 flood. Channelization of the reach downstream of the bridge has lead to significant changes in the channel. The accuracy of the scour observations, especially for the 2001 flood, is degraded due to the absence of a reliable reference surface.                                                                                               Contraction scour characteristics included in the database were taken from the WSPRO model.
The HEC-18 estimated post-scour elevations suggest that the bridge would have collapsed during both the 1979 and 2001 floods because the piling would have been undermined. Keeping the same subarea stationing limits for the post-scour section as were used for the pre-scour section so that a consistent top width could be determined, the average depths for pre- and post-scour conditions were determined for the overbank and the main channel. These pre- and post-scour depths were used to determine average contraction (mostly) scour depths in the overbank and main-channel areas.                                                                                                           April 5, 2001:  About 0, 8, and 2 ft of mostly contraction scour occurred in the left (south) overbank, main channel, and right (north) overbank, respectively. HEC-18 method suggested about 3, 19, and 4 ft of contraction scour in the left (south) overbank, main channel, and right (north) overbank, respectively. HEC-18 method for pressure-flow conditions suggested about 1, 19, and 2 ft of contraction scour in the left (south) overbank, main channel, and right (north) overbank, respectively.


Comments:
Contracted width does not include the width of the riprap protection (~150 ft) around pier #3 of the old bridge.


Comments:
The reference surface used to determine the reported contraction scour of 2 feet was established by inspection of a longitudinal profile through the SR 218 surveyed bridge reach.  The plot (shown in the longplot.jpg file in the supporting files) illustrated a natural degradation of the channel bed through the bridge opening due to the bend rather than contraction scour.  The contraction scour was measured below the bed elevation in the bend rather than average channel elevation in uncontracted sections further upstream and downstream (see Janesville_Topo.jpg in supporting files).  A spur dike extending upstream of the bridge’s right abutment forced the right floodplain flow to enter the channel approximately 100 feet upstream of the bridge at which point scour in the channel was observed.  The reference surface was established from a cross-section located upstream of the convergence between the floodplain and main channel flow.  The maximum contraction scour depth was ~5.7 feet and observed upstream of the bridges between pier #4 and #5.


Comments:
Contraction scour was computed as the difference in the mean bed elevation in the approach section and the contracted section as reported in Table 1. Contracted and uncontracted section variables taken directly from Table 1 in U.S. Geological Survey
Water-Resources Investigations 32-75 
Scour at Selected Bridge Sites in Alaska
By Vernon W. Norman
November 1975


Comments:
Contraction scour was computed as the difference in the mean bed elevation in the approach section and the contracted section as reported in Table 14, while accounting for the slope in the streambed. Since there was not contraction on 4/22 and little contraction on 9/2 it was determined that there was typically a 1 ft difference between the average bed elevation at the approach and contracted sections. This 1 ft difference is treated as the slope of the streambed. Differences on 9/4 greater than 1 ft are called contraction scour. Contracted and uncontracted section variables taken directly from Table 14 in U.S. Geological Survey
Water-Resources Investigations 32-75 
Scour at Selected Bridge Sites in Alaska
By Vernon W. Norman
November 1975


Comments:
The reported scour depth was taken from post-flood observations at the site. The maximum scour was 14 ft around pier #8. The contracted and uncontracted scour parameters reported in the database were taken from the HEC-2 model developed following the flood utilizing surveyd high-water marks. The model developed from field data showed that 25,000 to 30,000 cfs passed through the overflow bridge; the hydraulic parameters for measurement 1 are representative of the conveyance of 25,000 cfs.  --  The contraction at this site is most notably attributed to the severe constriction in the floodplain flow width created by extending the western approach fill 146 feet to accommodate the new shorter Galvin Road overflow bridge.  Although the hydraulic analysis for the new bridge revealed that the shorter structure would meet the Federal Emergency Management Agency’s (FEMA) requirement of less than 1-foot increase in the floodplain depth, the analysis did not consider the potential for scour.


Comments:
The reported scour depth was taken from post-flood observations at the site. The contracted and uncontracted scour parameters reported in the database were taken from the HEC-2 model developed following the flood utilizing surveyd high-water marks. The model developed from field data showed that 25,000 to 30,000 cfs passed through the overflow bridge; the hydraulic parameters for measurement 1 are representative of the conveyance of 30,000 cfs.  --  The contraction at this site is most notably attributed to the severe constriction in the floodplain flow width created by extending the western approach fill 146 feet to accommodate the new shorter Galvin Road overflow bridge.  Although the hydraulic analysis for the new bridge revealed that the shorter structure would meet the Federal Emergency Management Agency’s (FEMA) requirement of less than 1-foot increase in the floodplain depth, the analysis did not consider the potential for scour.


Comments:
The cont. scour depth entered in the database was determined from analysis of the surveyed cross-sections collected during the 9/17 - 9/18/01 post-flood survey.                                                                                                                WSPRO Results:     500- yr    Clear-Water Calculations Y1=5.20  D50=.59  Dm = .74  W2=81.0   Ys = 0 ft        100-yr  Clear-Water Calculations  Y1=3.95  D50=.59  Dm=.74  W2=81.0   Ys=0 ft  --------------   WSPRO contraction scour calculations were based on the bridge conditions after the 1986 flood, which prompted the MTDOT to lined the section through the bridge with riprap, hence the very large D50 and Dm values.  The grain size distribution found in this section and in the bed material section are representative of the material that was present prior to the 1986 flood. Since clear-water scour is assumed to take place and no other event has occurred since 1986 that forced the overflow bridge to convey water, post-flood surveys of the section provided a reasonable estimate of the scour that occurred during the 1986 flood.  The scour depths specified in this section were determined from these post-flood surveys.


Comments:
All contraction is on the right portion of the approach section, therefore eccentricity is 0.  It should be understood that although clear-water conditions are predicted for this flow regime, this site has the capabilities of experiencing live-bed conditions under slightly higher flows.  If debris accumulates during a flood event, it could have had a significant effect on the amount of contraction scour due to the relatively minimal contraction ratio.


Comments:
The cont. scour depth entered in the database was determined from analysis of the surveyed cross-sections collected during the 9/17 - 9/18/01 post-flood survey.

WSPRO Results:   500- yr    Clear-Water Calculations Y1=6.33  D50=.59  Dm=.74  W2=83.0   Ys = 0 ft         100-yr  Clear-Water Calculations  Y1=5.24  D50=.59  Dm=.74  W2=83   Ys=0 ft   --------------   WSPRO contraction scour calculations were based on the bridge conditions after the 1986 flood, which prompted the MTDOT to lined the section through the bridge with riprap, hence the very large D50 and Dm values.  The grain size distribution found in this section and in the bed material section are representative of the material that was present prior to the 1986 flood. Since clear-water scour is assumed to take place and no other event has occurred since 1986 that forced the overflow bridge to convey water, post-flood surveys of the section provided a reasonable estimate of the scour that occurred during the 1986 flood.  The scour depths specified in this section were determined from these post-flood surveys.


# Pier

Description:
Note: Elevations for bottom of footing are approximates, final elevations determined by engineer and contractor during construction.


Description:
Left pier when looking downstream, consists of 3 separate 3.75' diameter cylindrical piers.


Description:
Right pier when looking downstream, consists of 3 separate 3.75' diameter cylindrical piers.


Description:
Pier #1 is the left-most pier (looking downstream) and consists of two separate 3' diameter cylindrical piers with foudations supported by 10 batter piles.


Description:
Pier #2 is the right-most pier  (looking downstream) and consists of two separate 3' diameter cyclindrical piers with foudations supported by 10 batter piles.


Description:
Pier #1 is on the left, looking downstream and is a single concrete webbed structure.


Description:
Pier #2 is on the right, looking downstream and is a single concrete webbed structure.


Description:
Pier #1 is an intermediate pile bent consisting of 4 cylindrical timber piles.  Pier numbering is from left to right looking downstream.


Description:
Pier #2 is an intermediate pile bent consisting of 8 cylindrical timber piles.  Pier numbering is from left to right looking downstream.


Description:
Pier #3 is an intermediate pile bent consisting of 8 cylindrical timber piles.  Pier numbering is from left to right looking downstream.


Description:
Pier #4 is an intermediate pile bent consisting of 4 cylindrical timber piles.  Pier numbering is from left to right looking downstream.


Description:
The piers are numbered from right to left, looking downstream and consist of a group of 5-6 creosoted timber piles.  The piles do not have foundations but rather driven into the bed material until refusal (penetration averaged 12.3 feet).


Description:
Piers are numbered from left to right  looking downstream.
All piers have a uniform vertical profile.
Piers are 18 foot long, with hammer-head design at top.


Description:
Flow approached pier 4 at approximately 20 degree angle.
Piers are numbered from left to right  looking downstream.
All piers have a uniform vertical profile.
Piers are 18 foot long, with hammer-head design at top.


Description:
Flow approached pier 5 at approximately 22 degree angle.
Piers are numbered from left to right  looking downstream.
All piers have a uniform vertical profile.
Piers are 18 foot long, with hammer-head design at top.


Description:
Pier 6 was in eddy fence, but fence was reasonably aligned at pier.
Flow appoached pier 6 at 5 degree angle.
Piers are numbered from left to right  looking downstream.
All piers have a uniform vertical profile.
Piers are 18 foot long, with hammer-head design at top.


Description:
Pier #1 is on the right, looking downstream, and is supported by 82 concrete pilings driven to depths ranging from 660.28' to 637.28'.  The foundation is dumbell shaped with 15.5' squares on each end connected by a 5' by 14' rectangle.  In 1952, the pier was reinforced with stone rip-rap at a 2:1 slope from the top of the foundation due to a major scouring event that occurred in April, 1951.  The remaining exposed channel bottom between the piers was lined with stone rip-rap paving to an elevation of 680'.  Debris frequently accumulates in front of pier 1 and is a noted problem.


Description:
Pier #2 is on the left, looking downstream, and is supported by 82 concrete pilings driven to depths ranging from 665.96' and 654.96'.  The foundation is dumbell shaped with 15.5' squares on each end connected by a 5' by 14' rectangle.  In 1952, the pier was reinforced with stone rip-rap at a 2:1 slope from the top of the foundation due to a major scouring event that occurred in April, 1951.  The remaining exposed channel bottom between the piers was lined with stone rip-rap paving to an elevation of 680'.  Debris frequently accumulates in front of pier 2 and is a noted problem.


Description:
Pier #2 has a tendency to accumulate a rather large pile of debris during high-flow events.


Description:
The upper portion of the pier (whose height varies) is 5 ft wide and 20 ft long as described.  The lower 15 ft is a 7-ft-wide by 28-ft-long round-nose stem.  It rests on a 21-ft by 33-ft footing and a 24-ft by 36-ft seal, which are both 5 ft high and are founded on piles.


Description:
The pier is founded on a concrete-filled caisson.


Description:
This is an expansion pier.  It does not have a footing as large as at Pier 4 (fixed pier), and the elevation of the top of the footing is 3.5 ft lower than the elevation of the top of footing at Pier 4.  Scour depth at this pier is not affected by the foundation.


Description:
This is the only fixed pier at this bridge.  Scour was measured here with a single fixed transducer.


Description:
Although the site description of this pier (Norman 1975), indicates a pointed nose, the pier is founded on two concrete-filled sheet-piling caissons 15 ft in diameter whose centers are aligned with the flow.  For hydraulic purposes, the pier is two round piles or caissons.


Description:
This pier's width tapers from 2.5 ft wide at the cap to 5 ft wide at the footing.  It is perpendicular to the roadway but skewed approximately 35-40 degrees to the flow.


Description:
This pier tapers from 2.5 ft wide at the cap to 5 ft wide at the footing. It is perpendicular to the roadway but skewed approximately 35-40 degrees to the flow.


Description:
This pier is a little bit bigger than the other ones.  It tapers from 3 ft wide at the cap to 5 ft wide at the footing.  The piers are perpendicular to the roadway but are skewed approximately 35-40 degrees to the flow.


Description:
This pier varies from a 14-ft-wide round-nosed stem at the foundation to two 6-ft-diameter columns supporting the pier cap.  These are separated by a pointed 10-ft-wide stem with an extreme positive rake designed to resist ice forces. Pier is approx. parallel with high flows but skewed 10 deg. at low.


Description:
This pier (the only one with complete scour data) is identical to the other 5 piers.  It is a pedestal-type pier, 3.2 ft wide and spaced 92 ft apart from piers 4 & 6.  Information on the piers was sketchy in the report, containing no data on the footings, caps, etc.


Description:
This is a pile-bent pier with two concrete piles spaced 24 ft on centers. The lower portion of the pile, placed in a drilled shaft in the channel bed, is 7 ft in diameter.  The pile transitions to a 6 ft diameter above the channel bed.  The pile cap is above grade, just below the bridge deck.


Description:
Each bent has two piles spaced at approx. 26 ft on centers with a pile-cap pedestal supporting the bridge deck.  Each pile is 9.8 ft in diameter below grade and extends into a stiff clay layer.  Above grade, the piles taper to a 6-ft diameter.  Mid-level, there is a 1.5-ft web wall (elev. 212-238 ft).


Description:
The pier encases six concrete-filled pipe piles (length 44 ft and diameter 1.1 ft) spaced at 3.8 ft on centers.  The pile tip elevation was estimated from the plan drawings.  Value reported as pile cap elevation is instead the bottom elevation of the pier. A 36-ft cantilever beam caps the pier.


Description:
The concrete pier encases six 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)


Description:
The concrete pier encases five 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 2.


Description:
The concrete pier encases five 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 3.


Description:
The concrete pier encases five 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 4.


Description:
The concrete pier encases six 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 5.


Description:
The concrete pier encases six 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 6.


Description:
The concrete pier encases six 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 7.


Description:
The concrete pier encases six 8-inch by 8-inch steel "H" piles.  Pier width is 0.95 ft, pier length is 24 ft, and pier height is at least 10.5 ft (exact height is unknown).  Depth to pile tip is also unknown. (Detailed construction plans are unavailable.)  NO Pier coordinates exist for pier ID 8.


Description:
The pier is constructed from two 4-ft-diameter concrete-filled steel cylinders connected with a solid steel web. The total length is 21 ft and height is approximately 10-12 ft.  Detailed plans of the pier/footings are unavailable. Pier 1 is out-of-plumb, reportedly because of debris forces and scour.


Description:
The pier is constructed from two 4-ft-diameter concrete-filled steel cylinders connected with a solid steel web. The total length is 21 ft and height is approximately 10-12 ft.  Detailed plans of the pier/footings are unavailable. Pier 2 is cracked and failing, possibly because of debris forces and scour.  NO Pier coordinates exist for pier ID 2.


Description:
The pier is constructed from two 4-ft-diameter concrete-filled steel cylinders connected with a solid steel web. The total length is 21 ft and height is approximately 10-12 ft.  Detailed plans of the pier/footings are unavailable.  NO Pier coordinates exist for pier ID 3.


Description:
The concrete pier is 3.25 ft wide at the bottom tapering to 2 ft wide at the top. It is 90 ft long at the bottom tapering to 86.76 ft at the top. The pier is 13 ft high from the bottom up to the beam capping the pier. The foundataion is 35-ft-long pipe piles and "H" piles.


Description:
This pile bent at the right edge of water includes 5 concrete piles (1.25 ft square) spaced 6 ft apart on centers.  The bridge deck rests on the pile cap.   Pile length of 55 ft is estimated from 1100 ft piles/4 piers/5 piles per pier.


Description:
Pile bent C2 includes 5 concrete piles (1.25 ft square) spaced 6 ft apart on centers. This pile bent has a 3-ft-diameter concrete collar extending several ft above and below the waterline (approximately to low-tide elevation) for protection from ice.  The collar should not affect scour.  NO pier coordinates exist for pier ID C2.


Description:
Pile bent C3 includes 5 concrete piles (1.25 ft square) spaced 6 ft apart on centers. This pile bent has a 3-ft-diameter concrete collar extending several ft above and below the waterline (approximately to low-tide elevation) for protection from ice.  The collar should not affect scour.  NO pier coordinates exist for pier ID C3.


Description:
This pile bent at the left edge of water includes 5 concrete piles (1.25 ft square) spaced 6 ft apart on centers.  The bridge deck rests on the pile cap.   Pile length of 55 ft is estimated from 1100 ft piles/4 piers/5 piles per pier.  NO pier coordinates exist for pier ID C4.


Description:
The pile bent has eight 18-inch-wide piles. The first and last piles are battered at an angle of one horizontal to 4 vertical. A 3 by 2.5-ft concrete strut is just above the high-water line. A grout-filled nylon bag with mini- mum thickness of 6 inches covers the piles from the strut to the mud line.


Description:
The pile bent has eight 18-inch-wide piles. The first and last piles are battered at an angle of one horizontal to 4 vertical. A 3 by 2.5-ft concrete strut is just above the high-water line. A grout-filled nylon bag with mini- mum thickness of 6 inches covers the piles from the strut to the mud line.   The pile bent has eight 18-inch-wide piles.


Description:
The pile bent has eight 18-inch-wide piles. The first and last piles are battered at an angle of one horizontal to 4 vertical. A 3 by 2.5-ft concrete strut is just above the high-water line. A grout-filled nylon bag with mini-mum thickness of 6 inches covers the piles from the strut to the mud line.


Description:
The pile bent has eight 18-inch-wide piles. The first and last piles are battered at an angle of one horizontal to 4 vertical.  This pile bent does not have a strut.  A grout-filled nylon bag with minimum thickness of 6 inches covers the piles from the mud line upward 3.8 ft.


Description:
The geometries noted for this 'Pier' are for piers 2,3,4,5, and 21,22,23 & 24. These piers are not skewed to the bridge, and are skewed to the flow.  They are overbank piers.  The piles are 3 x 3 ft concrete squares, and are capped at the bridge-deck support, with no ground-line pile cap.


Description:
Geometries noted for this pier id are for piers 6,6.5, & 15.5 to 20.  Piles are angled out 10 deg. from vertical.  Five pairs of 2x2 ft conc. piles are spaced 5 ft apart, centerline to centerline (3 ft clearance) at cap, perpen-dicular to flow.  The piles make effective pier width for purposes of scour.


Description:
Pile cap is near high-tide elevation, so piles make effective width for scour.  Six pairs of 2x2 ft concrete piles are angled 10 deg. from vertical.  The piles are spaced about 5 ft apart, cl to cl (3 ft clearance) at pile cap, perpendicular to flow.


Description:
Pile cap is near high-tide elevation, so piles make effective width for scour.  Six pairs of 2x2 ft concrete piles are driven vertically and spaced 5 ft apart, cl to cl (3 ft clearance), perpendicular to flow.


Description:
Pile cap is near high-tide elevation, so piles make effective width for scour.  Six triplets and 2 pairs of 2x2 ft conc. piles are driven vertically.  Triplets are spaced 3.7 ft apart, cl to cl (1.7 ft clearance), perpendicular to flow.  The total number of piles is 22.


Description:
Pile cap is near high-tide elevation, so piles make effective width for scour.  Eight triplets of 2x2 ft conc. piers are driven vertically and spaced 3.7 ft apart, cl to cl (1.7 ft clearance), perpendicular to flow.  The total numberof piles is 24.


Description:
Pier 1 is at the left edge of water for low flows.  The pier tapers from 2.0 ft at the top to 3.8 ft at the base.  The footing is not exposed for any of the scour measurements.


Description:
Pier 2 is about 10 ft left of the right bank.  The pier tapers from 2.0 ft at the top to 3.8 ft at the base.  The footing is not exposed for any of the scour measurements.


Description:
Pier 3 is on the right overbank, about 70 ft from the right bank. The pier tapers from 2.0 ft at the top to 3.8 ft at the base.  The footing is not exposed for any of the scour measurements.


Description:
Pier 5 is located at approximately the top of the left bank of the main channel.


Description:
Pier 7 is in the channel near the thalweg.  Debris frequently collects on this pier during high flows, making depth soundings difficult or impossible near the pier nose.


Description:
Pier 8 is in the channel near the thalweg.  Debris frequently collects on this pier during high flows, making depth soundings difficult or impossible near the pier nose.


Description:
Pier 1 is on the left overbank during low flows.


Description:
Pier 2 is on the left overbank during low flows.


Description:
Pier 3 is near the left edge of water at low flows.


Description:
Pier 4 is in the main channel near the thalweg.  This pier frequently has log jams piled on it.


Description:
This round-nosed pier is on the upper right overbank area and rests on a square pile cap.


Description:
This round-nosed pier is on the upper right overbank area and rests on a square pile cap. The pier width is stepped.


Description:
The pier is located near the top bank on the lower right overbank area. The pier has an upper portion that is round nosed and a lower portion that is sharp nosed. The pier rests on a sharp-nosed pile cap.  The pier width and footing width are stepped.


Description:
The pier is located in the main channel of the river.  The pier has an upper portion that is round nosed and a lower portion that is sharp nosed.  The pier rests on a sharp-nosed pile cap.  The pier width and footing widths are stepped.


Description:
The pier is on the left overbank near the edge of the main channel.  The pier is round nosed and rests on a square pile cap.


Description:
Pier 1 is located at the edge of top bank.  The pier is 12 ft wide at the top and 14 ft wide at the bottom with the change occurring at elevation 165 ft. The foundation is a caisson with a minimum elevation of 80 ft.


Description:
Pier 2 is located on a lower terrace above the low-water channel.  The pier is 12 ft wide at the top and 14 ft wide at the bottom with the change occurring at elevation 165 ft. The foundation is a caisson with a minimum elevation of 80 ft.


Description:
Pier 3 is located in the main channel.  The pier is 12 ft wide at the top and 14 ft wide at the bottom with the change occuring at elevation 165 ft. The foundation is a caisson with a minimum elevation of 80 ft.


Description:
Pier 4 is located in the main channel.  The pier is 12 ft wide at the top and14 ft wide at the bottom with the change occurring at elevation 165 ft. The foundation is a caisson with a minimum elevation of 80 ft.


Description:
Pier 5 is located in the main channel at the left edge.  The pier is 12 ft wide at the top and 14 ft wide at the bottom with the change occurring at elevation 165 ft. The foundation is a caisson with a minimum elevation of 80 ft.


Description:
Pier 6 is located on the top bank.  The pier is 12 ft wide at the top and 14 ft wide a the bottom with the change occurring at elevation 165 ft. The foundation is a caisson with a minimum elevation of 80 ft.


Description:
The two sharp-nosed piers (5 ft wide and 41.7 ft long) and footers are skewed 30 degrees to the bridge and are aligned with the flow at most stages.  Each pier is a solid web for its entire length.  The piers extend 2 ft upstream of the bridge at the nose but are square and flush at the tail end.


Description:
This is the right-most of the three piers, which are 4-ft-wide by 32-ft-long and spaced 51 ft apart.  Each pier is a continuous web on poured footers,which probably extend to bedrock.   This pier has some riprap protection.


Description:
This is the middle of the three piers, which are 4-ft-wide by 32-ft-long and spaced 51 ft apart.  Each pier is a continuous web on poured footers,which probably extend to bedrock.  There is no riprap protection at this pier.  This pier tends to collect debris.


Description:
This is the left-most of the three piers, which are 4-ft-wide by 32-ft-long and spaced 51 ft apart.  Each pier is a continuous web on poured footers, which probably extend to bedrock.  There is no riprap protection at this pier.


Description:
Each pier, formed by the the convergence of two arches, increases in width with elevation from the 4-ft width at the base.  The face of each pier is flat.  The piers are spaced approximately 56 ft apart.


Description:
The pier consists of one row of five 16x16-inch concrete piles spaced 6.25 ft apart.


Description:
The pier has two rows of 16x16-inch concrete piles battered at 1 into 1 ft. One row has five piles spaced 6.25 ft apart, and the other row has four piles spaced 8.33 ft apart.  At top of piles (elev.279.2), rows are spaced 2.0 ft apart.  Bottom of cap is at elev. 278.1 ft.


Description:
The pier has two 3.5-ft-diameter concrete columns spaced 17 ft apart.  Columns have 11-ft-wide by 10-ft-long by 4.5-ft-deep concrete footings (with 3.5-ft-wide connecting webs) supported by eight 18-in concrete piles. There are three piles at the us side of the footing, two in middle, and three at the ds side.  

Pier coordinates for pier ID 17L:
          -1.75             255.7
          -1.75             281.2
           1.75             281.2
           1.75             276.7
          -1.75             276.7
           1.75             276.7
           1.75             255.7
            5.5             255.7
            5.5             251.2
           -5.5             251.2
           -5.5             255.7
           1.75             255.7


Description:
The pier has two 3.5-ft-diameter concrete columns spaced 17 ft apart.  Columns have 11-ft-wide by 10-ft-long by 4.5-ft-deep concrete footings (with 3.5-ft-wide connecting webs) supported by eight 18-in concrete piles. There are three piles at the us side of the footing, two in middle, and three at the ds side.  

Pier coordinates for pier ID 18L:
          -1.75             255.6
          -1.75             281.1
           1.75             281.1
           1.75             276.6
          -1.75             276.6
           1.75             276.6
           1.75             255.6
            5.5             255.6
            5.5             251.1
           -5.5             251.1
           -5.5             255.6
           1.75             255.6


Description:
Pier has two rows of 16x16-in concrete piles battered at 1 in to 1 ft. One row has five piles spaced 6.25 ft apart, and the other row has four piles spaced 8.33 ft apart.  At top of piles (elev. 279.2 ft), rows are spaced 2.0 ft apart.  Bottom of cap is at elev. 278.1 ft.


Description:
Pier consists of one row of five 16x16-inch concrete piles spaced 6.25 ft apart.


Description:
The pier has two rows of 16x16-inch concrete piles battered at 1 into 1 ft.  One row has five piles spaced 6.25 ft apart, and the other row has four piles spaced 8.33 ft apart.  At top of piles (elev.279.2), rows are spaced 2.0 ft apart.  Bottom of cap is at elev. 278.1 ft.


Description:
The pier has two 3.5-ft-diameter concrete columns spaced 17 ft apart.  Columns have 11-ft-wide by 10-ft-long by 4.5-ft-deep concrete footings (with 3.5-ft-wide connecting webs) supported by eight 18-in concrete piles.  There are three piles at the us side of the footing, two in middle, and three at the ds side.


Description:
Pier consist of two rows of 16x16-inch concrete piles battered at 1 into 1 ft.  One row has five piles spaced 6.25 ft apart, and the other row has four piles spaced 8.33 ft apart. At top of piles (elev.279.2), rows are spaced 2.0 ft apart.  Bottom of cap is at elev. 278.1 ft.


Description:
Pier consists of an 8-ft-diameter concrete column on a 15-ft-wide by
15-ft-long by 7.5-ft-deep concrete footing supported by 
20 14x14-inch concrete piles.


Description:
Pier consists of two 32-ft-high by 4.9-ft-long (at base) vertically tapered 
columns with a height of 9 ft at 4 ft wide, 11 ft at 5 ft wide, 12 ft at 6 ft 
wide connected by a 17.0-ft-long by 18-inch-wide web wall on a 10-ft-wide by 
35-ft-long by 20-ft-deep concrete footing supported by untreated wooden piles.


Description:
Pier consists of two 32-ft-high by 4.9-ft-long (at base) vertically tapered 
columns with a height of 9 ft at 4 ft wide, 11 ft at 5 ft wide, 12 ft at 6 ft 
wide connected by a 17.0-ft-long by 18-inch-wide web wall on a 10-ft-wide by 
35-ft-long by 20-ft-deep concrete footing supported by untreated wooden piles.

  Pier coordinates for pier ID 5:
           -3.0             115.1
           -3.0             126.9
           -2.5             127.1
           -2.5             137.9
           -2.0             138.1
           -2.0             147.1
            2.0             147.1
            2.0             138.1
            2.5             137.9
            2.5             127.1
            3.0             126.9
            3.0             115.1
            5.0             115.1
            5.0              94.4
           -5.0              94.4
           -5.0             115.1
            3.0             115.1


Description:
Pier consists of two 26.6-ft-high by 3.2-ft-long (at base) vertically tapered 
columns with a height of 11.3 ft at 2.5 ft wide by 2.5 ft long and 15.3 ft
at 3.2 ft wide by 3.2 ft long spaced 19.8 ft apart on two 5.2-ft-wide by 7.4-
ft-long footing (includes sheet-piling cofferdam that has been installed).

Pier coordinates for pier ID 7:
           -2.6             110.0
           -2.6             124.7
         -1.585             124.7
         -1.585             139.6
          -1.25             139.9
          -1.25             151.2
           1.25             151.2
           1.25             139.9
          1.585             139.6
          1.585             124.7
         -1.585             124.7
            2.6             124.7
            2.6             110.0


Description:
Pier consists of two 4-ft-diameter concrete columns spaced 17.0 ft apart.  Each column is on a 11.2-ft-wide, 8.5-ft-long, 4.0-ft-deep concrete footing supported by 12 18x18-in concrete piles.  There are four piles at the upstream 
side of the footing, four in the middle, and four at the downstream side.


Description:
Because pier is tapered, pier width is average of base and top-most widths.


Description:
See description for pier P1. Elevations of piers and footings are based on USCG dimensions from MDT drawing no. 9284.  No as-built information was used to confirm the elevations shown in this file.  Elevations are +/- 0.5 feet.


Description:
Because piers are tapered, pier width and length are based on avg exposed pier during 6/6/91 flooding.  Stationing is based on field measurements and does not relate to bridge plans.  Pier elevations relate to datum of MDT dwg. 3870, which closely approximates datum used in survey of sections (+/- 0.2 ft).


Description:
See description for pier 1.  Also pier 2 has been observed to experience the most scour.  Channel-geometry data (10/23/91) at exit and app sections were used to estimate reference surface at bridge for determining scour depth at pier 2 and to confirm lack of thalweg influence and lack of contraction scour.


Description:
Because pier is tapered, avg width and length are indicated. Channel-geometry 
data at exit and approach sections (8/28/92) was used to estimate reference 
surface at bridge for determining scour depth at pier 1 and to confirm lack of 
thalweg influence and lack of contraction scour.


Description:
Because pier is tapered, avg length and width are indicated.  Stationing is 
based on field measurements and does not relate to bridge plans.  Pier 
elevations relate to datum of MDT dwg. no. 3895, which closely approximates 
USCGS datum used in survey of sections (+/- 0.2 ft).


Description:
Data is based on dimensions shown on MDT dwgs 7042 and 7045, and local datum.  Although dwgs show a maximum difference of 0.35 ft in the base elevation of the four pier ftngs, ftng and pier coordinates used in this file are based on the assumption that all ftngs are at about the same base elevation.


Description:
See comments for P1.  Also, pier width indicated above is average of top and 
base widths (excluding ftng) and may not be the same as width described under 
pier scour measurements.


Description:
The flow angle of 30 degrees results in scour along the entire length of 
the right side of the pier.  The footing is undermined 2 ft.  Flow aligns 
with the pier before reaching the downstream side.


Description:
This is a concrete pier with a 9-ft-wide, 3.5-ft-thick footing.


Description:
The pier was out of water during low flow.  The top of the footing was 
partly exposed.


Description:
The pier was near the left edge of low water.  The footer was exposed 3.35 ft 
(0.75 ft from bottom of footer). 
An Eagle-Mach 1 fathometer and CR-10 were attached to pier for about 2 years.  
Instrumentation proved unsatisfactory.

Pier coordinates for pier ID 2:
          173.0             613.0
          173.0             617.0
          175.0             617.0
          175.0             635.5
          180.0             635.5
          180.0             617.0
          182.0             617.0
          182.0             613.0


Description:
The pier was located in the main flow.  The footer was exposed 0.9 ft.  
This footer is 3 ft lower than the footer at pier 2.


Description:
The pier is out of water except during extreme high flow.


Description:
The deepest scour is at this pier, despite having shallower and slower flow 
than at piers 2-3.  The bed material may not be consistent at piers.  Debris
at this pier has wedged into the scour hole, and it may be "armoring" the
hole.


Description:
The pier is out of water, except during very high flow.  The pier is founded on rock.


Description:
The pier is founded on rock.  It is susceptible to debris accumulation because it is located near the outside of a bend in the stream.


Description:
The pier is founded on rock at 1086 ft msl.  The elevation of the streambed was about 1092 ft msl.


Description:
The concrete pier is a solid wall with round nose.


Description:
This is a solid-wall concrete pier with round nose.


Description:
The piers are poured, formed concrete with a slight taper and round nose.


Description:
This is a concrete solid-wall pier with rounded nose.


Description:
The concrete pier is a solid wall with a rounded nose.


Description:
The concrete pier is a solid wall with a segmented, trianglar-shaped face.  
The pier width tapers from 3.75 ft at the footer to 2.75 ft at the top.
Note: All bridge elevation data in this section was obtained from
 the 1933 site plans, the msl datum was revised in 1965 by 4.06 feet.


Description:
This is a concrete, solid-wall pier with a round nose.


Description:
The three piers have the same dimensions (3 ft wide and 35 ft long), 
but are set at different elevations.  Each pier has a solid webb for its 
entire length.  Each pier rests on 20 piles spaced at 3.7 ft (35-40 ft long) 
and a pile cap.  The center pier is the only pier with the pile cap exposed.


Description:
The three piers, skewed 30 degrees to the bridge,  are 2.9-ft-wide, 32-ft-long solid webs constructed on wooden-pile foundations spaced 62 ft apart.  Each pier foundation consists of 18 piles 30-35 ft long spaced 3.6 ft apart under a pile cap.  The piers are slightly skewed to high flows.


Description:
Each pier, 2.5 ft wide and 43 ft long, is a continuous web resting on a
pile cap.  Piles are arranged is two rows of seven piles (seven pairs of 
piles).  The two rows of piles are 2.5 ft apart, and the pile pairs are 
7.0 ft apart.


Description:
This is the right-bank pier.  Each pier, 3.17 ft wide and 83 ft long, is a continuous web its entire length and is supported by pile footings.  Steel I-beam piles (54) are arranged in two rows approximately 3.5 ft apart and pile pairs are spaced 3.25 ft apart.  Pile length ranges from 11.5-21.0 ft.


Description:
This is the left-bank pier.  Each pier, 3.17 ft wide and 83 ft long, is a continuous web its entire length and is supported by pile footings.  Steel I-beam piles (54) are arranged in two rows approximately 3.5 ft apart and pile pairs are spaced 3.25 ft apart.  Pile length ranges from 11.5-21.0 ft.


Description:
The piers, 2 ft wide and 41 ft long, are a continuous web of uniform width 
supported by a footer.  The footer extends 1 ft beyond the ends of the pier, 
and the bottom 2 ft of the footer was keyed into undisturbed material 
without using forms.


Description:
The piers, 28-ft continuous webs resting on pile caps, taper 
from 2.25 ft wide at the base to 1.5 ft wide at the top.  Ten piles 
support each pier.


Description:
The concrete piers, continuous webs 2 ft wide and 30 ft long, are supported 
by footers on bedrock.  The piers are rounded on the upstream and downstream 
ends.  The footers are not exposed.


Description:
The three concrete piers, 2 ft wide and 29.5 ft long, are continuous webs 
supported by square footers keyed into bedrock.  The piers are aligned 
with the flow at most stages.


Description:
Pier 10 has a rectangular, caisson footing 46 feet long by 16 feet wide with it's base at elevation 243.0 feet and extending up to elevation 325.0.  From the top of the caisson a solid, round nosed section 42 feet long by 12 feet wide rises to elevation 360.0.  The nose of the pier is circular with a 6 foot radius.  Two tapered columns extend from elevation 360 to the bridge deck (elevation 431.08).  The columns are connected by a continuous web  from elevation 360.0 to 382.5 feet.  The columns are tapered and measure 9 feet wide at their base (elevation 360), and 6.5 feet wide at elevation 431.08 feet.  The columns have a stepped, square face which will be classified as square.


Description:
Pier 11 has a rectangular, caisson footing 52.5 feet long by 24 feet wide with it's base at elevation 256.0 feet and extending up to elevation 325.0.  From the top of the caisson a solid, round nosed section 48.5 feet long by 18 feet wide rises to elevation 360.0.  The nose of the pier is circular with a 9.0 foot radius.  Two tapered columns extend from elevation 360 to the bridge deck (elevation 440.1).  The columns are connected by a continuous, 3.5 foot wide web  from elevation 360.0 to 382.5 feet.  The columns are tapered and measure 15 feet wide at their base (elevation 360), and 11 feet wide at elevation 403.0 feet.  The columns have a stepped, square face which will be classified as square.


Description:
Pier 12 has a rectangular, caisson footing 46 feet long by 16 feet wide with it's base at elevation 314.0 feet and extending up to elevation 325.0.  From the top of the caisson a solid, round nosed section 42 feet long by 12 feet wide rises to elevation 360.0.  The nose of the pier is circular with a 6 foot radius.  Two tapered columns extend from elevation 360 to the bridge deck (elevation 441.651).  The columns are connected by a continuous web  from elevation 360.0 to 382.5 feet.  The columns are tapered and measure 9 feet wide at their base (elevation 360), and 6.5 feet wide at elevation 441.65 feet.  The columns have a stepped, square face which will be classified as square.


Description:
Pier 13 is in the flood plain on left bank.  Pier is two 3.5 ft sq posts
spaced 33 ft on center with a 3.5 ft square beam between the posts from elev.
705.61 to 709.11 ft.


Description:
Pier 12 is in the flood plain on left bank.  Pier is two 4 ft square posts
spaced 33.3 ft on center with a 4 ft square beam between posts from Elev.
705.35 to Elev. 709.35 ft.  Pier is turned about 9 degrees clockwise to be
parallel to railroad tracks adjacent.


Description:
Pier 11 is in flood plain on left bank with pile cap below grade. Pier is 8.3
ft wide at base tapering to 5.5 ft wide at top.  Ground level is at elev
704 ft at base. Not subject to scour.


Description:
Pier 10 is in left 1/3 of channel.  Pile cap is stepped.  Lower 8 ft is 31
ft wide, upper 8 ft is 27 ft wide.  Base of pier is 11.4 ft wide.  Pier
tapers to 7 ft wide at top at approx elev. 744 ft.


Description:
Pier 9 is in right 1/3 of channel.  Pile cap is stepped, Lower 8 ft is 35 ft
wide, upper 8 ft is 31 ft wide.  Base of pier is 11.3 ft wide.  Pier tapers to
7 ft wide at top. Approx elev. of top is 742 ft, about 34 ft above highest
water level expected.


Description:
Pier 8 is 8.67 ft wide at base, 4.5 ft wide at top. Pier is in flood plain on
right bank behind floodwall. Not subject to scour.  Ground at base is at Elev.
703 ft.


Description:
The concrete pier is a solid wall with round nose.
Pier width is 4.0 feet at base of footer and tapers uniformly at top to
3.0 feet wide.


Description:
The concrete pier is a solid wall with round nose.
Pier width 4.0 feet at base of footer and tapers uniformly at top to
3.0 feet wide.


Description:
The concrete pier is a solid wall with sharp nose.


Description:
Steel I-beam (1 foot estimated width) concrete capped piles
Spacing estimated to 4 feet wide.


Description:
Steel I-beam (estimated width 1 foot) concrete capped piles
Spacing estimated 4 feet.


Description:
Concrete solid wall pier, with a sharp face.


Description:
Concrete solid wall pier, with a rounded face.


Description:
This concrete pier is a solid wall with round nose.


Description:
The piers are pile bents consisting of 5, 16-inch diameter concrete piles spaced 9 ft apart in a single line.  The upstream and downstream piles are battered at 2 on 12.


Description:
The bridge was originally designed and constructed in the mid 1940s.  The original bridge had two twin-column piers located at the toe of the bank slopes.  The columns were hexagonal shaped, giving them a sharp upstream and downstream nose.  The foundations were poured footings with untreated timber piles beneath the footings.  The abutments had 45-degree wing walls both upstream and downstream.  In the early 1990s, the bridge was widened.  To accommodate the wider roadway a 20-inch round concrete-filled steel pile was placed upstream and downstream of each of the existing columns.  The upstream left column was reenforced with 6-inches of reenforced concrete from its base up to a level determined by the contractor in the field.  The abuments were widened and reinforced and new wing walls constructed.  The spill slopes at the abutments were graded to 2:1 on the left and 3.4 to 1 on the right.  The spill slopes were protected with grout to the waters edge at the time of construction, then large riprap was placed on the slope below the waterline.


Description:
Dual concrete columns with partial web walls. Each column, from bottom up: 9' x 6' x 4.5' (WxLxH) footings over 6 concrete piles (30' average in place); cylindrical sub-column 4.625' in diameter and 11.5' high with conical column above tapering from 4.625' to 3' in 19.625'; 3.5' x 23.5' x 2' cap; webwall from elevation 642.0' to cap.


Description:
Dual concrete columns with partial web walls. Each column, from bottom up: 11.5' x 9' x 4.5' (WxLxH) seal course over 9 concrete piles (34' average in place); footing of 7.5' x 6.5' x 3'; conical column tapering from 5.375' to 3' in 28.6'; 3.5' x 23.5' x 2' cap; webwall from elevation 635.0' to cap.


Description:
Dual concrete columns with partial web walls. Each column, from bottom up: 9' x 6' x 4.5' (WxLxH) footings over 6 concrete piles (28' average in place); cylindrical sub-column 4.625' in diameter and 11.5' high with conical column above tapering from 4.625' to 3' in 19.625'; 3.5' x 23.5' x 2' cap; webwall from elevation 642.0' to cap.


Description:
There are three piers at location #1, positioned at the upstream, centerline and downstream portion of the bridge.  None of the three piers are skewed to one another, but rather positioned in a straight line, parrallel to the flow.


Description:
There are three piers at location #2, positioned at the upstream, centerline and downstream portion of the bridge.  None of the three piers are skewed to one another, but rather positioned in a straight line, parrallel to the flow.


Description:
There are three piers at location #3, positioned at the upstream, centerline and downstream portion of the bridge.  None of the three piers are skewed to one another, but rather positioned in a straight line, parrallel to the flow.


# PierScour

Comments:
For this date, this is the only pier where scour could be actually measured.


Comments:
This scour measurement was estimated from partial fathometer trace.


Comments:
This scour measurement was estimated from soundings on cross sections at the bridge and from results obtained in July 1971.


Comments:
Submerged debris at the nose of the pier probably caused the scour depth to be about twice that expected if the debris had not been present.  It also probably caused the scour to move further downstream.


Comments:
This scour measurement was estimated from soundings on cross sections at the bridge and from results obtained in July 1971.  Submerged debris probably caued the scour depth to be twice that expected if debris had not been present and probably caused the scour to move downstream.


Comments:
Local scour was only studied at Pier 5 using four fixed transducers.  Although riprap was not visible at this pier during low flow, a "rock" was detected near the left side of the upstream caisson during a survey of the scour hole.  After the flood, riprap was found at about  the 1-ft elevation.

Bed-material samples on exposed bars contain material larger than the values from the sieve analysis.  The median diameter of the material just upstream from pier 5 is estimated to be between 5 and 10 mm.  The sigma reported is an average of the sigmas for the four samples. The D95, D84, and D16 were computed from the provided data.   D95, D84, and D16 were computed from the equation D50 * Sigma^(standard normal deviate of 95, 84 or 16).


Comments:
Scour was difficult to measure because the dune heights were of the same magnitude as the apparent depth of the local-scour holes and ambient-streambed elevation was hard to describe.  This is an expansion pier and scour depth was not affected by the foundation.


Scour was difficult to measure because the dune heights were of the same magnitude as the apparent depth of the local-scour holes and ambient-streambed elevation was hard to describe.  This is an expansion pier and scour depth was not affected by the foundation.


Comments:
Scour was difficult to measure because the dune heights were of the same magnitude as the apparent depth of the local-scour holes and ambient-streambed elevation was hard to describe.  This is an expansion pier and scour depth was not affected by the foundation.


Comments:
Scour was difficult to measure because the dune heights were of the same magnitude as the apparent depth of the local-scour holes, and ambient streambed elevation was hard to describe.  This is the only fixed pier of the 7 piers.


Comments:
Footing was exposed by scour.  Scour depth was hard to measure because dune heights were of the same magnitude as the apparent depth of the local-scour holes, and the ambient streambed was hard to describe.


Comments:
Footing was exposed by scour on this pier, the only one of the 7 to be a fixed pier.  Scour depth was difficult to measure because the dune heights were of the same magnitude as the apparent depth of local scour holes, and the ambient streambed was hard to describe.


Comments:
Scour was sampled using soundings from a sounding weight.  Turbulence was severe during high water.  Minimum bed elevation was near the nose of the pier.  The nose wave this pier created at high flow sheds almost all of the debris that the current directed toward it.


Comments:
Maximum observed scour occurred this date.  Turbulence was severe during high water.  Scour was measured using soundings from a sounding weight.  The nose wave this pier created during high flow shed almost all of the debris that the current directed toward it.  Minimum bed elevation was near nose of pier.


Comments:
Because of the skew to flow, water on the left side of the pier had a placid appearance, while the water surface on the right was extremely turbulent.  The only characteristic of the streambed profiles common to all four piers is minimum streambed elevation, which apparently was on pier's downstream end.


Comments:
Because of the skew to flow, water on the left side of the pier had a placid appearance, while the water surface on the right was extremely turbulent.  The only characteristic of the streambed profiles common to all four piers is minimum streambed elevation, which apparently was on pier's downstream end of the pier.


Comments:
Longitudinal profiles of the streambed beside the pier were obtained using the boat and fathometer.  Debris on the pier nose prevented the boat from getting closer than 10 ft.  A significant change in profile shape between two measurements on July 28 & 30 indicate a shift in angle of attack from < 5 deg to > 5.


Comments:
Fathometer traces show that this scour hole at pier 5 was probably the maximum scour that occurred at the bridge although shallow depths prevented accurate readings at the other piers.  NOTE:  The report contains data for remnant scour holes at other piers during low flow, but insufficient detail for entry here.


Comments:
Flow skew to the pier was 20 degrees at the nose  and 7 degrees at the tail.


Comments:
Flow skew to the pier was 20 degrees at the nose and zero degrees at the tail.


Comments:
The average approach velocity was 2.64 feet per second.  The scour hole is probably a remnant of earlier scour activity.


Comments:
Flow skew to the pier was 20 degrees at the nose and 7 degrees at the tail.


Comments:
The velocity reported is the average velocity of the approach cross section.
The scour hole may be a remnant from previous scour activity.  
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
Average approach section velocity was 2.40 feet per second.
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
The maximum scour-hole depth is to the right of the pier.


Comments:
Channel bottom rises in vicinity of the  pier.


Comments:
The reported velocity is the average velocity of the approach section.  The reference surface was difficult to determine at this pier, which is located at the channel thalweg.
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
The maximum scour-hole depth is to the left of the pier.
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
High velocity prevented depth measurement at the pier nose.  Scour depth estimated based on nearby measurements.  Actual scour depth may be larger than the estimate.


Comments:
High velocity and debris accumulation prevented depth measurement at the pier nose.  Scour depth estimated based on nearby measurements.  Actual scour depth may be larger than the estimate.


Comments:
The velocity reported is the average velocity of the approach cross section.
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
Debris pile prevented measurement of depth at pier nose.  Scour depth estimated based on nearby measurements.  Actual scour depth may be larger than the estimate.


Comments:
The maximum scour depth is to the right of the pier.


Comments:
The reported velocity is the average velocity in the approach cross section.
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
The maximum scour-hole depth is to the left of the pier.  The velocity reported is the average velocity in the approach cross section.
There was no skew measured during the October measurement, however, based on all previous measurements it is anticipated that skew would be present.  Skew was evident in an approach section collected in October but the stationing could not be aligned with the bridge. The skew reported is that of the previous measurement


Comments:
The channel thalweg coincides with the pier location for this measurement, making the accuracy less certain.


Comments:
Channel bottom elevation along the pier is higher at the downstream end than at the upstream end.  Flow channel near the pier may be largely a remnant of previous scour activity.


Comments:
Accuracy of local scour estimate is probably 1 foot.  Estimate is maximum scour for this cross section only and may not represent the maximum local scour at the pier.


Comments:
Measurement made from boat.  Depth computed as ws - ref. elev. at hole.  Velocity was measured at 15:09 at pier.  Scour-hole cl offset from pier cl by 10 ft.  Channel did have live-bed mat. entering scour hole, however at small rate of transport.  Two 2x2 ft conc. piles have an eff. width of 4 ft.


Comments:
Measurement made from boat.  Two 2x2 ft square concrete piles have effective width of 4 feet.  Channel was live-bed, but no large transport was ongoing.  Velocity was measured at pier at 17:34.  Flow depth computed as water-surface elevation minus reference elevation at scour holes.


Comments:
Channel geometry measurements were made by fathometer from boats.  Velocities measured real-time at pier.  Flow depth computed as water surface minus reference elevation at scour hole.  Two 2x2 ft concrete piles give an effective pier width of 4 ft.


Comments:
Channel geometry measurements were made by fathometer from boats.  Velocities measured real-time at pier.  Flow depth computed as water surface minus reference elevation at scour hole.  Three 2x2 ft concrete piles give an effective pier width of 6 ft.


Comments:
Channel geometry measurements were made by fathome


Comments:
Scour measurement was done as a discharge measurement with a 100-pound weight.


Comments:
The bed-material information reported is from bed-material sample no. 1, which was collected near pier 8.


Comments:
Bed-material information reported is from bed-material sample no. 1, which is a composite sample collected with a BM-54.  The bed material could be coarser that reported, as indicated by sample no. 2.  However, sample no. 2 was collected with a clamshell sampler, and significant fines may have been lost.


Comments:
Approach velocity is from a measurement on 5-18-90 at the upstream side of the upstream bridge (westbound).  No sediment samples were collected--sediment information was estimated from the Coushata data.


Comments:
Approach velocity was taken from measurement on 5-23-90 (no location recorded).  No sediment samples were collected--sediment information was estimated from the Coushatta data.


Comments:
Approach velocity was taken from measurement on 5-23-90 (no location recorded).  No sediment samples were collected--sediment information was estimated from the Coushata data.


Comments:
Velocity reported as approach velocity was actually measured at the downstream side of this bridge.  No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured at the upstream side of this bridge on 5-18-90.  No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured on the upstream side of this bridge on 5-18-90.  No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured on 5-23-90, but  no location was reported.  No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured on 5-23-90, but no location was reported.  No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured at the downstream side of this bridge.   No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured at the upstream side of this bridge on 5-18-90.   No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured at  the upstream side of this bridge on 5-18-90.   No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured on  5-23-90, but no location was recorded.   No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Velocity reported as approach velocity was actually measured on 5-23-90, but no location was recorded.   No sediment samples were collected--sediment sizes were estimated from the Coushatta data.


Comments:
Reference bed is at elev. 261.8 ft. 
Minimum bed elev. at the pier is at the downstream side at 256.9 ft.  
Scour-hole depth = 261.8 - 259.8 = 2.0 ft.  The downstream bed is not in a defined hole.


Comments:
Reference bed is at elev. 256.9 ft. 
Minimum bed elev. at the pier is at the downstream side at 254.4 ft.  
Scour-hole depth = 256.9 - 254.4 = 2.5  ft.


Comments:
Reference bed is at elev. 247.3 ft. 
Minimum bed elev. at the pier at the upstream side is at 247.3 ft. 
Scour-hole depth = 247.3 - 247.3 = 0 ft.


Comments:
Reference bed is at elev. 252.6 ft.
Minimum bed at the pier at the upstream side is at 252.6 ft.  
Scour-hole depth = 252.6 - 252.6 = 0 ft.  Pile is on edge of bank.  Bed elev. 
at downstream side is at 250.0 ft, but there is not defined hole.


Comments:
Reference bed is at elev. 242.2 ft.
Minimum bed is at downstream side at 239.4 ft, but it is not in a defined scour hole.  
Scour-hole depth = 242.2 - 240.9 = 1.3 ft.


Comments:
Reference bed is at elev. 244.6 ft. 
Minimum bed elev. At the pier is at the downstream side at 241.6 ft.  
Scour-hole depth = 244.6 - 241.6 = 3.0 ft.


Comments:
Reference bed is at elev. 242.4 ft. 
Minimum bed elev. at the pier is at the upstream side at 241.0 ft.  
Scour-hole depth = 242.4 - 241.0 = 1.4 ft.


Comments:
Reference bed is at elev. 246.7 ft.  Minimum bed elev.iIs at upstream side at 244.8 ft, but bed is at 245.3 ft for Dmax of the hole.  Scour-hole depth = 246.7 - 245.3 = 1.4 ft.  Scour-hole side slope was not determined--a tree was caught on a pile.


Comments:
Reference bed is at elev. 249.5 ft. 
Minimum bed elev. at pier is at the upstream side at 247.5 ft.  
Scour-hole depth = 249.5 -247.5 = 2.0 ft. 
Effective pier width is depth weighted using column and footing widths.


Comments:
Reference bed is at elev. 249.4 ft. 
Minimum bed elev. at pier is at upstream side at 245.8 ft.  
Scour--hole depth = 249.4 - 245.8 = 3.6 ft.  
Effective pier width is depth weighted using column and footing widths.


Comments:
Reference bed is at elev. 252.2 ft. 
Minimum bed elev. at pier is at upstream side at 248.1 ft.  
Scour-hole depth = 252.2 - 248.1 = 4.1 ft. 
Effective pier width is depth weighted using column and footing widths.


Comments:
Reference bed is at elev. 249.6 ft. 
Minimum bed elev. at the pier is at the upstream side at 248.0 ft.  
Scour-hole depth = 249.6 - 248.0 = 1.6 ft.  
Effective pier width is depth weighted using column and footing widths.


Comments:
Reference bed is at elev. 250.3 ft. 
Minimum bed elev. at the pier is at upstream side at 248.3 ft.  
Scour-hole depth = 250.3 - 248.3 = 2.0 ft.  
Effective pier width is depth weighted using column and footing widths.


Comments:
Reference bed is at elev. 251.3 ft.at upstream and downstream sides. 
Minimum bed at pier at downstream side is at 248.7 ft., and 248.8 ft. upstream.  
Scour-hole depth = 251.3 - 248.7 = 2.6 ft., 251.3 - 248.8 = 2.5 ft. upstream.  
Effective pier width is depth weighted using column and footing widths.


Comments:
Reference bed is at elev. 243.0 ft. 
Minimum bed elev. at the pier is at the upstream side at 241.6 ft.  
Scour-depth = 243.0 - 241.6 = 1.4 ft.


Comments:
Reference bed is at elev. 243.9 ft. 
Minimum bed elev. at the pier is at the upstream side at 241.0 ft.  
Scour-hole depth = 243.9 - 241.0 = 2.9 ft.


Comments:
Reference bed is at elev. 247.0 ft. 
Minimum bed elev. at the pier is at the downstream side at 244.9 ft.  
Scour-hole depth = 247.0 - 244.9 = 2.1 ft.


Comments:
Reference bed is at elev. 248.1 ft. Minimum bed elev. at pier is at upstream 
side at 246.5 ft.  Scour-hole depth = 248.1 - 246.5 = 1.6 ft. 
Effective pier width is a depth-weighted average of column, footing, and piling widths.


Comments:
Reference bed is at elev. 251.9 ft. 
Minimum bed elev. at the pier is at the upstream side at 248.0 ft. 
Scour-hole depth = 251.9 - 248.0 = 3.9 ft.  
Eff. pier width is a depth-weighted ave. of column, footing, and piling.


Comments:
Reference bed is at elev. 251.2 ft. 
Minimum bed elev. at pier at upstream side is at 245.5 ft.  
Scour-hole depth = 251.2 - 245.5 = 5.7 ft.  
Eff. pier width is a depth-weighted ave. of column, footing, and piling width.


Comments:
Reference bed is at elev. 250.6 ft. ft. 
Minimum bed elev. at pier is at upstream side is at 246.9 ft.  
Scour-hole depth = 250.6 - 246.9 = 3.7 ft.  
Eff. pier width is a depth-weighted ave. of column, footing, and piling width.


Comments:
Reference bed is at elev. 218.2 ft. 
Minimum bed is 3-4 ft upstream from pier at elev. 214.1 ft.  
Scour-hole depth = 218.2 - 214.1 = 4.1 ft..


Comments:
Reference bed is at downstream side at elev. 220.0 ft.
Minimum bed is at downstream side, 28 ft left of pier at elev. 216.8 ft.  
Scour-hole depth = 220.0 - 216.8 = 3.2 ft.  
Debris prevented soundings at the upstream side of pier.


Comments:
Reference bed is at elev. 217.7 ft. 
Minimum bed elev. recorded is at 214.8 ft.  
Scour-hole depth = 217.7 - 214.8 = 2.9 ft.  
Values were determined from FHWA reports and USGS discharge measurements.


Comments:
Reference bed is at elev. 217.0 ft.
 Minimum bed elev. recorded is at 214.1 ft.  
Scour-hole depth = 217.0 - 214.1 = 2.9 ft. 
Values were determined from FHWA reports and USGS discharge measurements.


Comments:
Reference bed is at elev. 218.7 ft.  Minimum bed elev. is at upstream side at
214.7 ft.  Scour-hole depth = 218.7 - 214.7 = 4.0 ft.  Minimum bed elevation 
at the pier was estimated from the measured scour-hole side slope and distance
to the pier.


Comments:
Reference bed is elev. 219.0 ft.  Minimum bed at upstream side is 212.6 ft.  
The maximum scour is affected by the footing, at 213.0 ft.  Scour is 219.0 - 
212.6 = 6.4 ft.  USSB section was supplemented with soundings at the pier 
(26037 213.4, 26041 212.6, 26045, 213.0) and 10 ft upstream from the pier.


Comments:
Reference bed is at 218.2 ft. Minimum bed (213.5 ft) was estimated by
projecting the measured scour-hole side slope downstream to pier.  Minimum 
bed at the pier face is affected by the top of the pier footing (213.0 ft.).


Comments:
Reference bed is at 217.5 ft.  Minimum bed (213.0 ft) at pier face is affected 
by the top of the footing (213.0 ft).  Cross section measured at upstream side 
of bridge was supplemented with soundings at pier (26117 213.0, 26125 214.8) 
and 5 ft upstream from pier (26111 214.6, 26121 215.2, 26131 214.5).


Comments:
Reference bed is at elev. 116.8 ft at downstream side.  No defined scour hole 
is on upstream side.  Minimum bed is at downstream side at 112.0 ft.  At 
upstream side, bed is at 116.4 ft.  Scour-hole depth  = 116.8 - 112.0 = 4.8 ft.  
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed is at elev. 115.8 ft.
Minimum bed elev. at pier is at upstream side at 113.5 ft.  
Scour-hole depth = 115.8 - 113.5 = 2.3 ft.  
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed is at elev. 111.0 ft.
Minimum bed elev. At pier is at upstream side at 105.7 ft.  
Scour-hole depth = 111.0 - 105.7 =5.3 ft.  
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed at downstream side of pier is at elev. 11.5 ft.  
Minimum bed elev. at pier is at downstream side at 107.6 ft.  
Scour-hole depth = 111.5 - 107.6 = 3.9 ft, at us side, 111.7 - 108.6 = 3.1 ft.  
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed is at elev. 112.7 ft.
Minimum bed elev. at pier is at upstream side at 107.0 ft (rough soundings).
Scour-hole depth = 112.7 - 107.0 = 5.7 ft.
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed is at elev. 110.3 ft at downstream side.
Minimum bed elev. at pier is at downstream side at 102.9 ft (rough soundings).
Scour-hole depth = 110.3 - 102.9 = 7.4 ft, at us side, 110.7 - 105.7 = 5.0 ft.
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed is at elev. 116.1 ft.
Minimum bed elev. at pier is at upstream side at 112.0 ft.
Scour-hole depth = 116.1 - 112.0 = 4.1 ft.
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed at upstream side is at elev 111.5 ft. Minimum bed at upstream
side is at 109.0 ft. At downstream side, bed is at 108.6 ft, but there is no
defined hole. Scour-hole depth = 111.5 - 109.0 = 2.5 ft.
Effective pier width is a depth-weighted average of the irregular pier widths.


Comments:
Reference bed is at elev. 110.3 ft.
Minimum bed elev. at pier is at upstream side at 105.4 ft.
Scour-hole depth = 110.3 - 105.4 = 4.9 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 111.4 ft.
Minimum bed elev. at pier is at downstream side at 104.9 ft.
Scour-hole depth = 111.4 - 104.9 = 6.5 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 109.6 ft at downstream side.
Minimum bed elev. at pier is at downstream side at 103.0 ft.
Scour-hole depth = 109.6 - 103.0 = 6.6 ft, at us side, 109.3 - 105.6 = 3.7 ft.
Eff. pier width is a depth-weighted ave. of the column, footing, and piling.


Comments:
Reference bed is at elev. 113.1 ft.
Minimum bed elev. at pier is at upstream side at 103.2 ft.
Scour-hole depth = 113.1 - 103.2 = 9.9 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 112.0 ft.
Minimum bed elev. at pier is upstream side at 104.5 ft.
Scour-hole depth = 112.0 - 104.5 = 7.5 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 110.5 ft.
Minimum bed elev. at pier is at upstream side of pier at 107.2 ft.
Scour-hole depth = 110.5 - 107.2 = 3.3 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 109.0 ft.
Minimum bed at pier is at upstream side at 107.0 ft.
Scour-hole depth = 109.0 - 107.0 = 2.0 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 111.5 ft.
Minimum bed elev. at pier is at downstream side at 107.0 ft.
Scour-hole depth = 111.5 - 107.0 = 4.5 ft, at us side: 112.0 - 107.9 = 4.1 ft.
Eff. pier width is a depth-weighted ave. of the column, footing, and piling.


Comments:
Reference bed is at elev. 113.5. Scour-hole side slope is rough due to close
proximity of bank. Minimum bed elev. at pier is at upstream side at 111.6 ft.
Scour-hole depth = 113.5 - 111.6 = 1.9 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 114.1 ft.
Minimum bed at upstream side is at 110.9 ft. At ds side, bed is at 110.4 ft.
Scour-hole depth = 114.1 - 110.9 = 3.2 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Reference bed is at elev. 111.3 ft.
Minimum bed elev. at pier is at upstream side at 109.9 ft.
Scour-hole depth = 111.3 - 109.9 = 1.4 ft. Effective pier width is a
depth-weighted average of the column, footing, and piling widths.


Comments:
Measurements made from bridge w/sounding wt and reel.  Effective pier width
is avg at WSEL and at reference surface used to measure to base of scour hole.
Approach velocity was estimated w/current meter at several stations located
away from pier acceleration zone using the two-point velocity method.


Comments:
Measurement made from bridge w/sounding wt and reel.  Effective pier width
is avg at WSEL and at reference surface used to measure to base of scour hole.
Approach velocity was estimated using surveyed channel-geometry data,
streamflow data, and REW and LEW elevations input to HP2 option of WSPRO.


Comments:
See description for P1 for 6/6/91.  Reference surface for determining scour at
P2 is estimated using 10/23/91 data for exit and approach overlayed on bridge
section data for 6/6/91.  Data for exit and approach sections dated 10/7/92
demonstrate no change in channel geometry for the two sections.


Comments:
See 6/18/92 description for P1.  See 6/6/91 description for P2 for discussion
of how reference surface was estimated for determining scour depth.


Comments:
See 6/23/93 description for P1.  See 6/6/91 description for P2 for discussion
of how reference surface was estimated for determining scour depth.


Comments:
Measurements made from bridge w/sounding wt and reel. Because current-meter
measurements were not taken, approach velocity was estimated using surveyed
channel-geometry data, streamflow data, and REW and LEW elevations input to
HP2 option of WSPRO.


Comments:
See 5/21/93 comments for P1.  For all P1 cases, reference surface for estim-
ating pier scour, top width, and side slope was determined on the basis of
surveyed sections (8/28/92) at approach and exit.


Comments:
See 5/21/93 and 5/27/93 comments for P1.  Also, for all P1 measurements,
determination of scour first required adjusting section for 35-degree skew.
The skew adjustment generally applies to all sections measured and all
resultant scour measurements.


Comments:
See 5/21/93 comments for P1 for explanation of how flow velocity was estimated
at P2.  All scour determinations first required adjusting section for 35-
degree skew to flow.


Comments:
Scour variables for P3 were estimated on the basis of measurements and results
for 9/23/92, 5/27/93, and 6/30/93.  Also see 5/21/93 comments for P1.


Comments:
All measurements at P3 to date involve estimation of velocity using HP2 output
of WSPRO.  See 5/21/93 comments for P1.


Comments:
Used soundings to left of pier to estimate approach-flow depth.  Measurements
made with four-wheel base and sounding weights.  Velocity measurements made
w/current meter for estimating approach flow velocity.


Comments:
Sounding measurements were made from u/s face of bridge w/four-wheel base,
reel, and 100-lb weight.  Velocities were measured w/current meter.  Reference
surface was estimated from section plot and surface was used to estimate
approach flow depth and other scour-hole variables.


Comments:
The sounding weight became lodged under the footing during measurement. Local
scour at the upstream side of the bridge (ussb) is 4.5 ft.  The maximum local
scour is 5.2 ft 25 ft downstream from ussb, based on the 8-28-91 cross
section. The ambient bed was lowered 0.4 ft.


Comments:
USGS measurement #653, 10-23-70.  Zero scour was measured.


Comments:
USGS measurement #675, 06-24-72.  Scour depth is based on ambient bed from
station 70 to 115.


Comments:
USGS measurement #708, 09-28-75.  Scour depth is based on ambient bed from
station 90.


Comments:
USGS measurement #736, 03-25-80.  Zero scour was measured.


Comments:
USGS measurement # 653, 10-23-70.  Zero scour was measured.


Comments:
USGS measurement #675, 06-24-72.  Scour based on ambient bed from station 165
to 228.


Comments:
USGS measurement # 708, 09-28-75.  Scour depth based on ambient bed at
station 245.


Comments:
USGS measurement # 736, 03-25-80.  Zero scour was measured.


Comments:
USGS measurement #675, 06-24-72.  Scour based on ambient bed from station 278
to 345. Other supporting data were used to help define the ambient bed.


Comments:
USGS measurement #708, 09-28-75.  Scour based on ambient bed from station 285.


Comments:
USGS measurement #675, 06-24-72.  Scour based on ambient bed from station 395
to 457.


Comments:
USGS measurement #708, 09-28-75.  Scour based on ambient bed from station
436 of measurement #680, 8-18-72 (streambed material placed around pier).


Comments:
USGS measurement #736, 03-25-80.  Elevation of scour hole dropped 1.0 ft from
measurement #708 (1975) to measurement #736 (1980).  Added  to 2.3 ft previous
local scour results in 3.3 ft "total" local scour used in USGS national scour
study.  The New York study analyzes this scour separately.


Comments:
USGS measurement #653, 10-23-70.  Scour based on ambient bed from station 520
to 580.


Comments:
USGS measurement #675, 06-24-72.  Scour based on ambient bed from station 470
to 590 of measurement #676 (6-25-72).


Comments:
USGS measurement #736, 03-25-80.  Elevation of scour hole dropped 0.8 ft from
measurement #708 (1975) to measurement #736 (1980).  Added to the previous
local scour of 2.2 ft results in 3.0 ft "total" local scour used in USGS
national scour study. Each scour is analyzed separately in the New York study.


Comments:
USGS measurement #653, 10-23-70.  Scour based on ambient bed from station 640.


Comments:
USGS measurement #675, 06-24-72.  Scour based on ambient bed from station 603
and ambient bed from station 600-640 of measurement #653 (1970).


Comments:
The scour is assumed to have occurred during the record 1987 flood.
Hydraulic data are based on 52,000 cfs flowing under the bridge, excluding
about 25,000 cfs bypassing bridge.  The scour depth is based on the ambient
bed from stations 152-194 for 1989-92 inspections.


Comments:
The scour is assumed to have occurred during the record 1987 flood.
Hydraulic data are based on 52,000 cfs flowing under the bridge, excluding
about 25,000 cfs bypassing bridge.  The scour depth is based on the ambient
bed from stations 242-284 for 1989-92 inspections.


Comments:
Scour depth is based on the ambient bed from station 234-250.  It is assumed
that the highest previous flow in 1979 produced the scour.  However, high
flows in 1977, 1984, and 1986 may have contributed to the scour.


Comments:
Same as pier 2 except ambient bed is station 367-384.


Comments:
Same as pier 2 except ambient bed is station 484-524.
Scour is deeper at pier 4 than at piers 2 and 3 despite lower velocities.  The
precise cause in unknown, but it could be related to possible differences in
bed material or the presence of debris at pier 4.


Comments:
NYSDOT measurement extends from 30 ft upstream to 30 ft downstream from pier
3 at 5-ft increments along left side of pier. Local scour is based on change
in ambient bed from station -10 (10 ft upstream) to station 5 (5 ft downstream
from pier nose). NYSDOT 1986-88 x-sections: 0001=right side 0002=left side.


Comments:
The measurements in 1989-92 all indicate about 3.1 ft of scour.
The scour is assumed to have occurred during the 1955 flood.


Comments:
Bed-material samples were collected during low-flow on 9/12/90.


Comments:
Bed-material samples were collected during low-flow on 10/2/90.
Water-surface slope was 0.00065.


Comments:
There is scour at the right pier only and there is no apparent,
significant contraction scour.  Bed-material samples were collected during
low flow on 9/6/90.  Water-surface slope was 0.00080.


Comments:
The bed-material sample for pier 1 could not be analyzed because of standing
water.  For the 5/16/90 scour measurement, the bridge-section composite
bed-material sample D50 value of 10.2 mm was used for pier 1.
Water-surface slope was 0.00153.


Comments:
Refer to comments for pier 1 scour measurement of 5/16/90, as the same
situation is applicable for this scour measurement, (Use D50 of 10.2 mm).
The accuracy of the 12/19/90 scour-hole depth was estimated to be 1.0 foot,
because of ambient-bed elevation uncertainty. Water-surface slope was 0.00158.


Comments:
The bed-material sample was collected on 8/31/90.
The water-surface slope was 0.00158.


Comments:
The top width of the scour hole at pier 1 (20 ft) seems quite wide--yet from
a check of the data, this value appears reasonable.  Possibly, a large
debris pile may have been on pier 1 prior to data collection.  The bed-
material sample was collected during low flow.


Comments:
The large top width of the scour hole (35 ft) was doubled checked.  Refer to
comment on 8/22/90 pier 1 measurement.  Submerged debris may possibly have
reduced the scour depth that occurred with the increased flow and velocity.
The bed sample was collected during low flow.  W.S. slope was 0.00135.


Comments:
Field data indicates the possibility that debris was near the pier during
scour measurement.  Soundings could be made in the vicinity of pier 1 with
effort.  Water-surface slope was 0.00018.


Comments:
Bed-material samples were collected during low flow on 8/20/90. Two samples
were collected at Pier 1 on 8/20/90: The first sample was collected in the
scour hole (D50 is 5.0 mm), and the second sample was collected 2 feet
upstream from the scour hole (D50 is 0.83 mm). W.S. slope was 0.00096.


Comments:
Bed-material samples were collected during low flow on 8/20/90.
Refer to comment for scour measurement on 5/16/90.
Water-surface slope was 0.00081.


Comments:
Bed-material samples were collected during low flow on 8/20/90.
Refer to comment for scour measurement on 5/16/90.
Water-surface slope was 0.00299.


Comments:
Bed-material samples were collected during low flow on 8/20/90.  Two samples
were collected at Pier 2 on 8/20/90: The first sample was collected in the
scour hole (D50 is 17 mm), and the second sample was collected 4 feet
upstream from the scour hole (D50 is 23.5 mm). W.S. slope was 0.00096.


Comments:
A large, tightly interwoven debris pile was found on pier 1 when the site
was initially established in December 1989, and it was removed by county
highway crews around March 1990.


Comments:
See comments for 5/17/90 scour measurment.


Comments:
Accuracy of local scour measurement is probably 1 foot.  Estimate of local
scour is for this cross section only and may not represent maximum local scour
at the pier.


Comments:
Accuarcy of local scour estimate is probably 1 foot.  Estimate is maximum
scour for this cross section only and may not represent the maximum local
scour at the pier.


Comments:
The scour depth is probably not valid where
the velocity is zero (remnant hole).


Comments:
Accuracy of local scour estimate is probably 1 foot.  Estimate is maximum
scour for this cross section only and may not represent the maximum local
scour at the pier.


Comments:
Water surface elevation - 388.4.  The reference elevation was determined to be 314.5 after careful analysis of contour plots of the detailed data.  The minimum bed elevation was 291.2.  The volume of the scour hole was computed to be 113260 cu. ft.  The pier width varies with the detph, and it's depth-weighted average width thus increase with decreasing depth.  Exposed portions of the pier below the local-scour reference surface elevation were not used in computing the pier width.  The location of the maximum scour depth is at the upstream left corner of the pier, as expected because of the slight skew of the flow.  Scour did not develop along the left side of the pier even with a skew of 11 degrees.


Comments:
Water-surface elevation - 386.4. The reference elevation was determined to be 313 after careful analysis of contour plots of the detailed data.  The minimum bed elevation was 292.6.  The volume of the scour hole was computed to be 126282 cu. ft.  The pier width varies with the detph, and it's depth-weighted average width thus increase with decreasing depth.  Exposed portions of the pier below the local-scour reference surface elevation were not used in computing the pier width.  The location of the maximum scour depth is at the upstream left corner of the pier, as expected because of the slight skew of the flow.


Comments:
Water-surface elevation - 372.6. The reference elevation was determined to be 317.8 after careful analysis of contour plots of the detailed data.  The minimum bed elevation was 296.4.  The volume of the scour hole was computed to be 149830 cu. ft.  The pier width varies with the detph, and it's depth-weighted average width thus increase with decreasing depth.  Exposed portions of the pier below the local-scour reference surface elevation were not used in computing the pier width.  The location of the maximum scour depth is at the upstream left corner of the pier, as expected because of the slight skew of the flow.


Comments:
Adjacent to this pier, the bed scoured down to the top of the footing for a length of at least 10 ft at the downstream end of the pier.  The minimum streambed elevation occurred downstream of the pier.  The depth of scour to be expected in the absence of the footing probably wouldn't be significant.


Comments:
Because of the skew to flow, water on the left side of the pier had a placid appearance, while the water surface on the right was extremely turbulent.  The only characteristic common to all four piers was the minimum streambed elevation, which apparently was located at the downstream end of the piers.


Comments:
Note:  For all measurements, the side slope of scour hole is horizontal
distance per foot change in elevation of stream bed in the scour hole.
Note:  For all measurements, bed material samples were not obtained in 1969.
Note:  The width of the pier was calculated as the depth weighed average pier width.


Comments:
The width of the pier was calculated as the depth weighed average pier width.


Comments:
A deep scour hole did not develop around pier 10. Practically no scour occured
in the left 1/2 of channel until after peak.  In 8 days following peak, the
river bed to left of pier 10 scoured out nearly 5 ft which did not fill in
as occured around pier 9.
The width of the pier was calculated as the depth weighed average pier width.


Comments:
Note:  For all measurements, side slope of scour hole is horizontal distance
per foot change in stream bed elevation in the scour hole.
The width of the pier was calculated as the depth weighed average pier width.


Comments:
Bed-material sample collected during low flow 7/30/92.


Comments:
The bed-material sample was collected after the scour measurement on 
10/15/92.


Comments:
Bed-material sample collected during low flow 8/21/91.


Comments:
Bed-material sample collected during low flow 9/10/92.


Comments:
The bed-material sample was collected during low flow on 7/9/92.
The water-surface slope was 0.00299.


Comments:
The bed-material sample was collected during low flow on 7/9/92.
The water-surface slope was 0.00091.


Comments:
The bed-material sample was collected during low flow on
The water-surface slope was 0.00780.


Comments:
The bed-material sample was collected during low flow on XXXXXX
The water-surface slope was 0.00780.


Comments:
The bed-material sample was collected during low flow on 7/2/92.
The water-surface slope was 0.00053.


Comments:
The bed-material sample was collected during low flow on 7/2/92.
The water-surface slope was 0.00168.


Comments:
Bed-material sample collected during low flow 6/19/91.
No bed-material sample obtained for this pier during 1992.


Comments:
Bed-material sample collected during low flow 9/17/91.


Comments:
Bed-material sample collected during low flow 9/17/91


Comments:
Bed-material sample collected during low flow 10/7/92.


Comments:
The bed-material sample was collected during low flow on 6/29/92.
The water-surface slope was 0.00060.


Comments:
The bed-material sample was collected during low flow on xxxxxx.


Comments:
The bed-material sample was collected during low flow on xxxxx.


Comments:
Fathometer data was collected and used to estimate bed-geometry.


Comments:
Fathometer data was used to estimate bed geometry.


Comments:
Bed-material sample collected during low flow 6/18/92.


Comments:
The bed-material sample was collected during low flow on XXXXX.
The water-surface slope was 0.00038.


Comments:
The bed-material sample was collected during low flow on XXXXXX.
The water-surface slope was 0.00038.


Comments:
Bed-material sample collected during low flow 10/5/92.


Comments:
Bed-material sample collected during low flow 6/27/92


Comments:
The data collected on 10/22/94 and 10/23/94 were considered one measurement and are reported as collected on 10/23/94.  The classification of the scour present at this site was difficult.  The scour was caused primarily by the large debris accumulation on bent 6, but determining if it should be classified as pier or contraction scour was difficult as the scour patterns showed signs of both.  It was not possible to separate the components at this complex site.  Because the scour originated at the bent and general degradation of the streambed across the cross section was not observed separate from debris on bents 6 and 7 it was determined that the scour should be classified as local scour with significant debris effects.  

The inspection reports show that the bottom of the scour hole was about –47 ft msl on both sides of bent 6 prior to the flood.  During the flood an elevation of –51.6 was measured along the left side and an elevation of -46.1 ft msl on the right side of bent 6.  Inspection reports also show that the hole apparently refilled from an elevation of  -46 to -35 ft msl along the left side and from –45 to –42 along the right side of bent 6, at the upstream edge of the bridge (which did not represent the deepest portion of the scour holes).

Although the surficial bed material is generally noncohesive the scour reached a clay layer near elevation –52 ft msl between bents 5 and 6.  This clay layer appears to have restricted further scour. The length and shape of the scour hole between bents 5 and 6 may be affected by the restricting clay layer and contraction effects of the left bank.  The borings show the clay layer to be at about –48 ft msl between bents 6 and 7 where the scour reach about –46.1 ft msl, and the volume of the scour hole was considerably less. 

The reference surface was difficult to determine, as the bridge is located at a channel crossing as the flow moves from the left to the right bank.  During high flow, crossings may fill and then scour as the flow recedes.  After careful study of the thalweg pattern, an elevation of –27 ft msl was selected as the expected elevation of the channel bed in the absence of the pier and debris.


Comments:
An initial check survey of the bridge on July 14, 1993 resulted in the establishment of this site as a detailed study site.  Detailed bathymetric data were collected on July 17 and 19, 1993; however, only average approach velocities were measured on these dates because of the inability of a 1,200 kHz BB-ADCP to measure velocities accurately under these extreme conditions.  Detailed bathymetric and three-dimensional velocities were measured at this site on August 17 and September 16, 1993.  No times are recorded with the measurements as a detailed measurement takes a half to a full day to complete.

The water-surface elevations initially peaked at an elevation of 420.7 on July 19, but additional rain resulted in a slightly higher peak in the following weeks.  No scour data were collected during this second peak.

The sediment transport upstream from pier 9 was characterized by 6 to 8 ft dunes; upstream from pier 8 dunes were somewhat smaller.

The depth of scour for each measurement was measured from a reference surface that was subjectively established based on a visual analysis of a 3-dimensional representation of the site.  The presence of dunes made identification of the reference surface difficult and uncertainty is the major contributing factor to the accuracy presented for each measurement. 

The configuration of the piers may have reduced scour due the stair-stepped design.  However, scour reached several feet below the top of the seals at piers 8 and 9 but did not threaten the stability of the bridge.


Comments:
Channel cross sections were measured at the Martin Luther King Bridge on July 15, 1993.  The cross section along the upstream edge of the bridge clearly showed a scour hole at pier 10 that is 13.5 ft deep.  The width of pier 10 varies with depth; the weighted average pier width, which does not include the width of the footing or caisson is 17.9 ft.  The pier is sharp nosed (but with a flat internal angle) for the main part of the pier, and the caisson and footing are round nosed.  The flow was aligned with the pier.  Approach velocities were estimated from a discharge measurement on the Mississippi River made the same day at the Poplar Street Bridge on I-70, which is about ¾ mile downstream from the Martin Luther King Bridge.  A nearly straight channel alignment and similarity of the measured cross-sectional areas and channel shape at the two bridges allowed the discharge measurement made at Poplar Street Bridge to be transferred with little error to the Martin Luther King Bridge.  The discharge measured on July 15, 1993 was 804,000 cfs and the mean velocity of the subsection of the river containing pier 10 was 8.6 ft/sec.


Comments:
Bed-material sample collected during low flow on 6/30/1992


Comments:
The scour value represent computed pier scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data) and hydraulic parameters were etimated with a WSPRO simulation.  The effective pier diameter is calculated using Melville & Dongel (1992) wherein the effect of a debris raft is converted to an effective pier diameter based on the thickness of the raft (assumed to be the approach depth divided by 3.4 = (15.4/3.4) = 4.53) and the diameter of the raft (approximated from discharge notes as 44 feet).  The computed contraction scour was 1.2 feet, for a total scour of 16.5 feet.  The actual measured total scour on this date was 17.2 feet (depth below "equilibrium bed" from measurement notes).


Comments:
The scour value represent computed pier scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data) and hydraulic parameters were etimated with a WSPRO simulation.  The effective pier diameter is calculated using Melville & Dongel (1992) wherein the effect of a debris raft is converted to an effective pier diameter based on the thickness of the raft (assumed to be the approach depth divided by 3.4 = (19.1/3.4) = 5.62) and the diameter of the raft (approximated from discharge notes as 70 feet).  The computed contraction scour was 0.0 feet, for a total scour of 17.1 feet.  The actual measured total scour on this date was 17.1 feet (depth below "equilibrium bed" from measurement notes).


Comments:
The scour value represent computed pier scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data) and hydraulic parameters were etimated with a WSPRO simulation.  The effective pier diameter is calculated using Melville & Dongel (1992) wherein the effect of a debris raft is converted to an effective pier diameter based on the thickness of the raft (assumed to be the approach depth divided by 3.4 = (18.0/3.4) = 5.30) and the diameter of the raft (approximated from discharge notes as 70 feet).  The computed contraction scour was 0.0 feet, for a total scour of 19.2 feet.  The actual measured total scour on this date was 20.0 feet (depth below "equilibrium bed" from measurement notes).


Comments:
The scour value represent computed pier scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data) and hydraulic parameters were etimated with a WSPRO simulation.  The effective pier diameter is calculated using Melville & Dongel (1992) wherein the effect of a debris raft is converted to an effective pier diameter based on the thickness of the raft (assumed to be the approach depth divided by 3.4 = (17.1/3.4) = 5.03) and the diameter of the raft (approximated from discharge notes as 70 feet).  The computed contraction scour was 0.4 feet, for a total scour of 21.5 feet.  The actual measured total scour on this date was 20.0 feet (depth below "equilibrium bed" from measurement notes).


Comments:
The scour value represent computed pier scour from an "equilibrium bed" elevation (established in Nov, 1999, based on survey and historical data) and hydraulic parameters were etimated with a WSPRO simulation.  The effective pier diameter is calculated using Melville & Dongel (1992) wherein the effect of a debris raft is converted to an effective pier diameter based on the thickness of the raft (assumed to be the approach depth divided by 3.4 = (19.1/3.4) = 5.62) and the diameter of the raft (approximated from discharge notes as 70 feet).  The computed contraction scour was 0.0 feet, for a total scour of 12.8 feet.  The actual measured total scour on this date was 11.8 feet (depth below "equilibrium bed" from measurement notes).


Comments:
Pier scour totally shifted from pier 1 to pier 2 during the period between measurements on 6/6/97 and 6/18/97.

WSPRO Results:
100-yr (HEC-18)
Qbridge  K1   K2   K3   a      Y1          V1     Fr      Ys
 (cfs)                            (ft)     (ft)         (fps)            (ft)
11,400  .90   1.0  1.1  4.0   14.87    10.86   .50   9.3

500-yr  (HEC-18)
Qbridge  K1   K2   K3   a      Y1          V1     Fr      Ys
 (cfs)                            (ft)     (ft)         (fps)            (ft)
12400   .90  1.0  1.1  4.0   15.55     10.49  .47    9.2


Comments:
See 5/21/93 comments for P1. Reference surface for estim-ating pier scour, top width, and side slope was determined on the basis of surveyed sections (8/2/92) at approach and exit and bridge opening (9/23/92).


Comments:
See 5/21/93 comments for P1. Reference surface for estimating pier scour, top width, and side slope was determined on the basis of surveyed sections (8/2/92) at approach and exit and bridge opening (9/23/92).


Comments:
Although local pier scour around the base of the piles may have contributed to the total scour depth and failure of the piles, it was determined by NHC to be insignificant compared to the contraction scour.  Therefore, no measurement or computations of abutment scour were made at the Galvin Road overflow bridge.


Comments:
The pier scour depth entered in the database was determined from analysis of the surveyed cross-sections collected during the 9/17 - 9/18/01 post-flood survey.

WSPRO Results:
100-yr (HEC-18)
Qbridge  K1   K2   K3   a      Y1          V1     Fr      Ys
 (cfs)                            (ft)     (ft)         (fps)            (ft)
4,570    1.0  1.0  1.1  2.0  11.54      8.26   .43   5.6

500-yr  (HEC-18)
Qbridge  K1   K2   K3   a      Y1          V1     Fr      Ys
 (cfs)                            (ft)     (ft)         (fps)            (ft)
5,690    1.0  1.0  1.1  2.0  11.54      10.29   .53   6.2


Comments:
The pier scour depth entered in the database was determined from analysis of the surveyed cross-sections collected during the 9/17 - 9/18/01 post-flood survey.

WSPRO Results:
100-yr (HEC-18)
Qbridge  K1   K2   K3   a      Y1          V1     Fr      Ys
 (cfs)                            (ft)     (ft)         (fps)            (ft)
4,570    1.0  1.0  1.1  2.0  11.54      8.26   .43    5.6

500-yr  (HEC-18)
Qbridge  K1   K2   K3   a      Y1          V1     Fr      Ys
 (cfs)                            (ft)     (ft)         (fps)            (ft)
5,690    1.0  1.0  1.1  2.0  11.54      10.29   .53   6.2


Comments:
Although pier #2 has a tendency to accumulate a rather large pile of debris during high-flow events, nothing was present during the measurements on 6/11/96.


# Site

SiteName:
Red River at S.R. 3032 near Shreveport, LA, W.B.

Description:
The S.R. 3032 bridge over the Red River is referred to as the Barksdale Bridge
and connects Shreveport and Bossier City.  The flood plain is of low relief
with numerous oxbow lakes.  However, at the bridge the flood plain is narrowed
by levees on both sides.  The site consists of two bridges--the upstream
bridge is the westbound lane of S.R. 3032.  The river is straight for more
than 10 channel widths upstream and downstream from this bridge.  No bed-
material samples were available for this site, so samples collected during the
same event at Coushatta, located about 50 miles downstream, will be used.
 
                         Bed-Material Sample Numbers:
                   Left side       Center         Right side
Above bridge        8703           8704              8705
Below bridge        8706           8707              8708

This entry is for the upstream or westbound bridge.
The stage and discharge hydrographs are from the Corps of Engineers gage at
Shreveport, which is located about 2 miles upstream from the bridge.  The peak
stages reported are at the bridge.  The drainage area reported is from the
Corps of Engineers gage at Shreveport.
Approach and exit sections were surveyed on 5-18-90 using a Raytheon
fathometer.  The survey was from tree-line to tree-line.  However,
these cross sections appear to be 8-10 ft higher than the cross sections
collected at the bridge and low-water cross sections taken from 1968-69
and 1980-81 hydrographic surveys published by the U.S. Army Corps of
Engineers, New Orleans District.  However, the elevation of the low-water
sections did agree reasonably well with the ambient bed elevation of the     
cross sections collected at the bridge during the flood.  Because of
these discrepencies associated with the elevation of the approach and exit
sections, no contraction scour is reported based on these data.  The shapes
of the approach and exit sections were used to assist in the determination
of the ambient bed for the local scour reported herein.  The approach and
exit sections are included as part of this data set because of their use in
determining the ambient bed, however, their usefulness for other purposes
is questionable based on the information presented above.

DescElevREf:
R.P. #1 set on upstream (westbound) bridge, on upstream side of bridge,
chiseled square on top of handrail 40 ft west (rt) of centerline of pier #4,
which is at Hwy Plans sta 103+48, 1340 ft from left abutment.
Elevation for R.P. #1 was determined by taping up:
  Finished grade centerline elevation at piers 3 and 4 = 226.4 ft (msl)
  Taped up centerline to wheel guard (0.75) to concrete handrail (2.05)
Elevation at R.P. #1 = 229.2 = 226.4 + 0.75 + 2.05


SiteName:
Youghiogheny River at S.R.42 at Friendsville, MD

Description:
The site is in Friendsville, Maryland at the State Highway 42 bridge
crossing the Youghiogheny River, 0.8 miles upstream from the mouth.  The
bridge is 155 ft long and has two 5-ft-wide piers on footers spaced 53 ft
apart.  The sharp-nosed piers and footers, skewed 30 degrees to the bridge
deck, are aligned with the flow at most stages.  The piers extend 2 ft
upstream of the bridge at the nose but are square and flush with the bridge
at the tail end.  Bedrock is probably located several feet below the gravel
and cobble channel bed.  A reservoir provides some regulation of flow at this
site.  Peak flows generally recede rapidly and the velocity is very fast
(> 7 ft/sec).  The right bank has houses right up to the top of the bank, and
the left bank has a gravel road at the top and houses along the road.

DescElevREf:
The datum of the gage is 1487.33 ft.  The datum of the wire weight (COE)
at the bridge (approximately  0.5 miles downstream) is 1472.58.  The datum
of the original bridge plans (assumed 100.00 ft elevation on corner of step)
is approximately 1394.64.  Wire-weight readings were taken on approximately
half the discharge measurements made at the bridge.  A relation was computed
between the wire-weight reading and the stage at the gage.  The maximum error
between predicted wire-weight and actual wire-weight readings was 0.30 ft.


SiteName:
Big Pipe Creek at S.R. 194 at Bruceville, MD

Description:
The site is located at Bruceville, Maryland at the State Highway 194 bridge
crossing Big Pipe Creek.  This is 3.5 miles upstream of the confluence with
Little Big Pipe Creek at Detour, Maryland.  The bridge is 200 ft long and
has three 4-ft-wide, 32-ft-long piers spaced 51 ft apart.  Each pier is a
continuous web constructed on poured footers, which probably extend down
to bedrock.  The bridge has a constant slope from the left bank (366.70 ft)
to the right bank (357.86 ft).  The bridge has flow-through abutments and
should not be overtopped during high flow.  (Flow would possibly go over the
roadway on the right bank.)

DescElevREf:
All elevations are given in MSL.  The gage datum is 336.88 ft.
BM-1 (1976): Bronze tablet stamped "V 81 RESET 1976" located on highway
bridge, 4.8 miles south along State Highway 194 from first junction with
State Highway 97 in the center of Taneytown, Md.  The tablet is located
in sidewalk on the southeast abutment of bridge number 6035.  It is 23 ft
northwest of telephone pole number 55, 15.8 ft east of the center of State
Highway 194, 5 ft north of the south edge of the sidewalk, and 2.4 ft east
of the wheel guard.  The elevation is 367.401 ft NVGD.
RM-1 (1947): Standard USGS bronze tablet set in the top of the upper intake
headwall at the gage 300 feet downstream of the bridge.  The elevation is
3.326 ft gage datum. (The headwall is cracked.)
RM-7 (1989): Railroad spike located in telephone pole number 55, 20 ft
shoreward from left upstream end of bridge.  The elevation is 31.204 ft
gage datum, 368.088 ft NVGD.
RP-2 (1989): Chiseled square on the upstream side of the walkway on the
bridge, 80 ft streamward from BM V-81.  The elevation is 25.982 ft gage
datum, 362.866 ft NVGD.


SiteName:
Choptank River at S.R. 287 near Goldsboro, MD

Description:
The site is located near Goldsboro, Maryland at the State Highway 287
bridge crossing the Choptank River.  The bridge is 240 ft long and has
four arch-supported spans.   Each pier, formed by the the convergence of
two arches, increases in width with elevation from the 4-ft width at
the base.  The face of each pier is flat.  The abutments are outside
the arches on each end.  Plans are not available for this structure.
Flow is through the left two arches most of the time.  Debris can clog
the arched passages and cause backwater and pressure flow.  Existing scour
holes are probably from a 1967 storm.

DescElevREf:
P-78-1942, located 0.5 miles west of the bridge, is at elevation 46.088 ft
MSL.
RM1, at elevation 28.229 ft, is a lag bolt in a poplar tree with four trunks
located 30 ft northeast of bridge (upstream on left bank).  The bolt is
1.5 ft above the ground.
MP1, at elevation 29.383 ft, is a cross is the outside edge of a steel
strap at station 41 on the upstream side of the bridge
MP2, at elevation 29.232 ft, is a cross in the outside edge of a steel
strap at station 42 on the downstream side of the bridge.


SiteName:
Pearl River at westbound S.R. 25 at Jackson, MS

Description:
This is an 1,180-ft-long bridge crossing the Pearl River at Jackson at
river mile 292.5. At this crossing, State Highway 25 is also known as
Lakeland Drive. This entry is for the westbound lanes, which are upstream
from the eastbound lanes. The bridge has a span arrangement of 15 at 40 ft,
1 at 90 ft, 1 at 120 ft, 1 at 90 ft, and 7 at 40 ft from right to left (west
to east). The 40-ft spans are supported by single-pile bents (2L-15L and
20L-25L), the 90-ft spans are supported by a double-pile bent (16L & 19L) and
a main pier (17L & 18L), and the 120-ft span is supported by two main piers
(17L & 18L). The main piers consist of two 3.5-ft-diameter columns on a
pile-supported footing. The pile bents consist of 16x16-in piles. A 75-ft-long
spur dike is located at the right (west) abutment, and a 150-ft-long spur dike
is located at the left (east) abutment.
  Scour data were collected during high and low flows using a fathometer.
The flow velocities approaching the bridge piers were determined from
velocity soundings during discharge measurements obtained at the upstream side
of the bridge. Ground-pentrating radar was also used at the site in July 1992
to detect infilling of scour holes.
  On April 28, 1993, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected:
Cross    Distance
Section  Upstream  Sample   Comments
    1       8 ft     1     Bed at about mid-span between bents 16-17L.
    1       8 ft     2     Bed in vicinity of main piers 17-18L.
    2     400 ft     3     Mid-channel.
    2     400 ft     4     Left part channel.
    3     800 ft     5     Mid-to-left part of channel.  

The right part of the channel bed at cross sections 2 & 3 seems to be
mostly silty clay. Bed sample no. 1 was used for bents 15-16L and sample
no. 2 was used for main piers 17-18L. For pile bents 12-14L, the material
is a clay with a cohesion of about 240 lb/ft2 and an angle of internal
friction of about 27 degrees, as determined from shear-strength tests on
Sept. 20, 1991.

DescElevREf:
RP-3.-- Chiseled square on top of light-pole base on upstream side of
upstream bridge near right (east) edge of channel (Elev. 289.41 ft).
RP-4.-- Chiseled square on top of upstream handrail near RP-3 on
upstream side of upstream bridge (Elev. 291.18 ft).


SiteName:
Pearl River at eastbound S.R. 25 at Jackson, MS

Description:
This is an 1,140-ft-long bridge crossing the Pearl River at Jackson at
river mile 292.5. At this crossing, State Highway 25 is also known as
Lakeland Drive. This entry is for the eastbound lanes, which are down-
stream from the westbound lanes. The bridge has a span arrangement of 15
at 40 ft, 1 at 90 ft, 1 at 120 ft, 1 at 90 ft, and 6 at 40 ft from right
to left (west to east). The 40-ft spans are supported by single-pile
bents (2R-15R & 20R-24R), the 90-ft spans are supported by a double-
pile bent (16R & 19R) and a main pier (17R & 18R), and the 120-ft span is
supported by two main piers (17R & 18R). The main piers consist of two 3.5-
ft-diameter columns on a pile-supported footing. The pile bents consist of
16x16-in piles. The bridge is 88 ft downstream from the upstream side of
the westbound-lane bridge.
  Scour data were collected during high and low flows using a fathometer.
The flow velocities approaching the bridge piers were determined from
velocity soundings during discharge measurements obtained at the upstream side
of the upstream bridge, about 88 ft upstream. Ground-pentrating radar was also
used at the site in July 1992 to detect infilling of scour holes.
  On April 28, 1993, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected:


Cross    Distance
Section  Upstream  Sample   Comments
    1     100 ft     1     Bed at about mid-span between bents 16-17L.
    1     100 ft     2     Bed in vicinity of main piers 17-18L.
    2     500 ft     3     Mid-channel.
    2     500 ft     4     Left part channel.
    3     900 ft     5     Mid-to-left part of channel.  

  The right part of the channel bed at cross sections 2 & 3 seems to be
mostly silty clay. Bed sample no.1 was used for bents 14-16R and sample
no.2 was used for main piers 17-18R. For pile bent 12-13R, the material
is a clay with a cohesion of about 240 lb/ft2 and an angle of internal
friction of about 27 degrees, as determined from shear-strength tests on
Sept.20, 1991.


SiteName:
Homochitto River at U.S. 84 at Eddiceton, MS

Description:
This is a 560-ft-long bridge crossing the Homochitto River about 0.8 mi east
of Eddiceton. This bridge has six 8-ft-diameter interior pier bents supporting
seven 80-ft-long spans. Three of the piers (Nos.3-5) are within the low-water
channel. The bridge deck is flat. A 150-ft-long spur dike is located at the
right (west) abutment. The bridge is skewed about 10 degrees from normal to
the channel and about 20 degrees from normal to the flood plain.
  Scour data were collected during high flows using a fathometer and during
low flows by standard surveys. The bridge piers are inset about 12 ft
from the upstream side of the bridge. During high-flow measurements, rubber
balls (flotation devices) were used to float the transducer downstream to
the upstream side of the pier. Channel sections were sounded on the upstream
and downstream sides of the bridge and, in some cases, additional soundings
were made close to the upstream side of the inset piers.  Because a complete
cross section could not usually be obtained along the face of the inset
piers, the scour-hole top width and side slope are not defined in most
cases.
  The flow velocities approaching the bridge piers were determined from
velocity soundings during discharge measurements obtained at the upstream side
of the bridge.
  On November 18, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples:

Cross    Distance
Section  Upstream  Sample   Comments
    1       0 ft     1     Mostly gravel, some sand.
    1     300 ft     2     Mostly gravel.
    2     550 ft     3     Mostly sand.

From available bed samples, the bed material seems to be gap-graded,
indicating a mixture of uniform sand and uniform gravel. Bed sample no.1 was
considered most representative of the bed material at the base of pier Nos. 4-
6.
  On September 18, 1990, gravel bars and 2- to 3-ft-high dunes were visible
downstream of the bridge on the right (west) part of the low-water channel.
From observations of water surface during flood-discharge measurements, waves
were visible. Therefore, a dune bed form seems likely at this site during high
flows.

DescElevREf:
Chiseled square on top of downstream handrail near center of channel set on
February 15, 1990. (Elev. 246.66 ft)
BM84V-5(1975)-- Bronze disk set in the the north end of the left (east)
                abutment of the main-channel bridge, about 4 ft lower than the
                highway. (Elev. 240.442 ft)


SiteName:
Knik River at Old Glenn Highway near Palmer, AK

Description:
This site is located at bridge 539 where it crosses the Knik River at mile 39 on the original Glenn Highway about 7 miles south of Palmer, Alaska.  The bridge opening is 2000 ft long. The Knik River is a braided glacial stream.  It drains an area of
approximately 1200 square miles, over half of which consists of glaciers.  The braided channel narrows from 3 miles wide at the terminus of Knik Glacier to less than 0.5 miles at the bridge.  In the vicinity of the bridge, the streambed consists of sand and gravel and some cobbles.  Daily discharges have been determined at this site since October 1959.  The average flow during the period October 1959 to October 1965 was 6,960 cfs.  For a number of years, annual peaks were caused by the breakout of a glacier-dammed lake, Lake George.  Scour during the 1966 breakout is reported herein.  As of the time of this report (Nov 1975), no breakout had occured since 1966 because the Knik Glacier, which caused the annual ice dam, began to retreat.  A description of the Lake George breakout and the possibility of its recurrence is given by Post and Mayo (1971). The fifth pier from the left bank was instrumented with four fixed transducers, and depths to the streambed below each transducer were
recorded by fathometer.  For more information on some of the methods and purpose of this study, see the location description for the Susitna River at Sunshine, AK.  A new bridge was built at the site in 1975 after the cessation of the outburst floods and its approaches constrict the flow of the Knik River. The embankments for the new bridge are rip rapped and spur dikes extend upstream beyond the old bridge.


SiteName:
Susitna River at S.R. 3 near Sunshine, AK

Description:
This study site is located on the Susitna River at mile 104 of the Anchorage-
Fairbanks Highway, about 3.2 miles west of Sunshine and 10.5 miles downstream
from the mouth of the Talkeetna River.  The Susitna River basin above the
bridge site covers about 11,500 square miles.  Less than 15 percent of the
area is occupied by glaciers.  In the vicinity of the bridge site the river
channel is braided and consists of multiple bars and islands.  Surface bed
material consists of gravel and cobbles and some sand.
Floodflows on the Susitna result from snow melt in the spring and from rain-
fall combined with glacial melt water in mid to late summer.  Records of flood
data have been collected about 50 miles upstream on the Susitna River at Gold
Creek since 1949.  The peak flow occurred June 7, 1964.  In 14 of these years,
floods occurred in June.  The mean annual flood for the scour site was
estimated to be about 80,000 cfs.  Information on floods in the Susitna River
during the summer of 1971 is given by Lamke (1972).
The data herein were collected as part of a study and report on general scour
at bridge crossings and local scour at bridge piers at sites in south-central
and interior Alaska during 1965-72.  The purpose of the study was to collect
scour data at bridge sites and compare the results with existing laboratory
data, field data,  and predicted values from selected scour formulas.
The report includes a detailed description of the physical setting,
hydraulic characteristics, and channel geometry at low and high flows to
assist the reader in developing background knowledge on the scour phenomenon
in various situations.
For the study, all indications of scour were considered to be related to
either channel contraction or localized flow conditions at piers and abutments
(local scour).  All of the scour conditions probably occurred when there was
significant bedload transport throughout the streams and Froude Numbers were
less than 1, because scour at high flows was followed by fill.  Information
was obtained from floods greater than or equal to the mean annual flood.
Soundings to determine cross-sectional profiles, longitudinal
profiles, and scour-hole depths were generally obtained with a Raytheon Model
DE119 D recording fathometer.  Transducers used with the fathometer produced a
8-degree beam width.
Equipment used to make soundings, measure velocities, and make discharge
measurements were standard USGS equipment as described by Buchanan
and Somers (1969).  This equipment consists of the "B" reel, Price Type AA
current meters, and sounding weights ranging from 50 to 100 lbs.
Streambed-material samples were collected using samplers appropriate to stream
velocities.  Streambeds of sand and small gravel were sampled using a US-BM54.
A locally constructed drag sampler was used in conjunction with a 100-lb
sounding weight to sample bed material in gravel and cobble streams.
Water-surface elevations were measured using standard surveying instruments
and techniques.  River stages were recorded by automatic recorders or by
measuring down from a fixed point using a wire-weight gage.
Photographs and surveys were used to aid in interpreting channel patterns,
variations in channel cross-sectional shapes, and velocity distributions.

DescElevREf:
Elevations given for pier definitions are to mean sea level.  Elevations given
for all stage data (including the hydrograph) and channel cross-section
coordinates are given with reference to the gage datum, 208.35 ft (63.50 m)


Description:
This study site is located 7.5 miles downstream from the site at
Palmer, Alaska.  It is 10 miles southwest of the village of Eklutna.  The
bridge at this site is 1500 ft long and crosses a channel of the Knik River at
a 20-degree angle.  Its seven round-nosed piers are spaced about 200 ft apart
and aligned with the flow.
The Knik River at this location has a braided channel, and the islands are
inundated at flood stage.  The channel streambed consisted of sand and gravel
and was in a dune regime at the time of the peak discharge.  In the study
channel the river begins to widen as it flows beneath the Alaska Railroad
Bridge, about 2000 ft upstream from the highway bridge, and continues to widen
for about 0.5 mile where it merges with the Matanuska River to form the upper
end of Knik Arm.  Tides reach the highway bridge, but even at flood stage
their effect probably is insignificant.
The high-water data in this report is the latest flood breakout (as of Nov
1975) in glacier-dammed Lake George.  Such breakouts often caused annual
peaks from 1959-1965, but they had not occurred since 1966 because the Knik
Glacier, which caused the annual ice dam, began to retreat.
For this study, the fourth pier from the left bank was instrumented with a
single transducer at the nose of the pier.  Depth to the streambed below the
transducer was recorded by fathometer.
For more information on the methods of sampling and purpose of this study,
see the Location description for the Susitna River near Sunshine.


SiteName:
Tazlina River at Richardson Hwy (S.R. 4)  nr Glennallen, AK

Description:
This study site is located at bridge 573 at mile 116.2 on the Richardson
Highway where it crosses the Tazlina River, 2 miles upstream from its
confluence with the Copper River.  It is 5 miles southeast of Glennallen.
The Tazlina River flows from a large glacier-fed lake about 26 miles west of
the study site.  The variations in discharge in the Tazlina River are subdued
by the lake.  Almost annually one of several glacier-dammed lakes above the
lake breaks out to produce floodflows in the river.  Post and Mayo discuss
these lake breakouts in their report on glacier-dammed lakes.  Stream-gaging
records have been maintained at the bridge since 1951.  Recorded annual peaks
range from a low of 15,300 cfs in 1956 to a high of 60,700 cfs in 1962.  The
mean-annual and 50-year recurrence-interval floods are about 25,000 and
78,000 cfs respectively.
Brice (1971) suggests that the recent history of the Tazlina River has been
one of slow degradation.
There is a large meander in the river about 4,000 ft upstream from the bridge,
which may eventually be cut off by erosion.
Alternate bars composed largely of cobbles and gravel but containing
occasional boulders are located in the study area.  Heavy riprap protection is
provided on both banks at the bridge opening and on the right bank for a
distance of 200 ft upstream from the bridge.
The data included in this report were collected during a flood in Sept 1971
(Q = 39,700 cfs).  Its recurrence interval is about 6 years.


Description:
This study site is located at bridge 524, which spans the Tanana River at mile
281 on the Richardson Highway, and is 0.5 miles northwest of Big Delta.  The
bridge at this site is 784 ft long and consists of one overhead-truss span
399 ft long and four girder spans each about 95 ft long, supported by four
round-nosed concrete piers.  Upstream from the bridge, the Tanana River
channel is braided and contains gravel bars and islands.  Immediately down-
stream from the bridge the Delta River empties into the Tanana River and forms
a delta.  This forces the Tanana River into a narrow channel against a bluff
on the opposite bank, which creates turbulence and has caused the bed of the
stream to scour a large hole to a depth of about 40 ft.  The streambed in the
vicinity of the bridge is composed of sand, gravel, and some cobbles.
The drainage area of the bridge is about 13,500 square miles, a small part of
which is covered by glaciers.  Daily discharge was recorded at this site for
8 years during the period 1949 through 1957.  The annual peaks observed during
that time ranged from 37,600 cfs to 62,800 cfs.  Mean-annual and 50-year peak
flows were approximately 49,000 cfs and 67,000 cfs, respectively.  Stage-
discharge relations were very poor because of the alternate advance and
retreat of the controlling delta.  Most of the measurements in this data
set were made in 1971.


Description:
This study site is located at bridge 202, which crosses the Tanana River at
the town of Nenana on the Anchorage-Fairbanks Highway.  The principal bridge
consists of two 500-ft overhead-truss spans supported in the center by a
single pier.  Not all of the flow of the Tanana River passes beneath this
main bridge because a bridged side channel conveys water at high flows.  The
drainage area of the Tanana River upstream from Nenana is approximately 25,600
square miles, a small part of which is covered by glaciers.
The Nenana River enters the Tanana River about 200 ft downstream from the
bridge.  Upstream and downstream from the site, the Tanana River exhibits a
meandering pattern.  About 1 mile upstream from the bridge, a rock bluff
resists a northward migration of the river and forces it into a channel
extending in a west-southwestward direction.  About 2,000 ft downstream from
the bridge, the river again turns to the north around the western end of
low-lying hills. The bridge is located at a crossover of the river channel.
Crossovers on a meandering channel usually are characterized by scouring
during low and medium flow and filling during high flows.  At the bridge, the
left or south bank has been stabilized by vertical bulkheads which form a
loading dock for commercial rail and barge operations.  Particle-size analyses
of streambed material show that it is comprised of sand and gravel.
Streamflow-gaging records have been maintained at Nenana since 1962.  The
mean-annual and 50-year floods are approximately 84,000 cfs and 168,000 cfs,
respectively.
The measurements included in this study were made in 1967.  The maximum
discharge was 174,000 cfs.


SiteName:
Snow River at Seward Highway (S.R. 9)  near Seward, AK

Description:
This study site is located at bridge 605 over the Snow River at mile 18.5 on
the Seward Highway, about 16 miles north of Seward, Alaska.  The 648-ft bridge
is of girder design consisting of seven spans supported by six round-nosed
pedestal-type piers.  Two spur dikes force the flow of the river to pass
through the opening parallel to the pier alignment.
Upstream from the bridge, the Snow River is a braided channel covering the
entire valley width of almost 1 mile.  Prior to the 1966 construction of the
present bridge, three bridge openings spanned the river's flow.  When the
present two bridges were constructed, the right channel was blocked completely
and bridge 605 was designed to handle the majority of the entire river flow.
Downstream from the bridge, the river enters Kenai Lake, which may cause some
backwater effect on the flow beneath the bridge when the lake level is high.
The surface streambed material in the vicinity of the bridge ranges from fine
sand to coarse gravel.  The foundation study along the centerline of the
bridge conducted by the State of Alaska, Department of Highways, indicates
silt and sand containing some gravel to a depth of about 100 ft.
Much of the approximately 150 square miles drainage basin of the Snow River
upstream from the bridge is covered by glaciers.  One glacier, known locally
as the Snow River Glacier, dams an unnamed lake from which water is released,
causing flooding. The breakout occurs at 2- to 3-year intervals.  During the
period 1961-1965, the USGS operated a gaging station about 10 miles upstream
from bridge 605.  The peak discharge during that period was 25,000 cfs.
During August and September 1970, the USGS operated a temporary gaging station
3 miles upstream from the bridge.  The flood that occured during this period
peaked on Sept 22 at a discharge of 17,800 cfs.  The majority of data
presented in this study were collected during that flood. An estimated peak flood of 
55,000 cfs occurred in August 1967.

DescElevREf:
Gage datum is 1.0 ft above mean sea level.


Description:
This site is located at the U.S. 71 bridge crossing the Red River at Index,
Arkansas, near the border with Texas.  The site is in the Coastal Plain
Province, which is underlain by alluvial deposits and other unconsolidated
sediments.  The channel bed consists primarily of fine sands, silts, and
clays.

DescElevREf:
Structure elevations are from the bridge plans.


Description:
This site is located at the I-30 bridge crossing the Red River near Fulton,
Arkansas, near the border with Texas.  The site is in the Coastal Plain
Province, which is underlain by alluvial deposits and other unconsolidated
sediments.  The channel bed consists primarily of fine sands, silts, and
clays.

DescElevREf:
Structure elevations entered are from the bridge construction plans.


Description:
This site is located at the U.S. 82 bridge crossing the Red River at Garland,
Arkansas, near the border with Texas and Louisiana.  The site is in the
Coastal Plain Province, which is underlain by alluvial deposits and other
unconsolidated sediments.  The channel bed consists primarily of fine sands,
silts, and clays.

DescElevREf:
Structure elevations given are from the bridge construction plans.


SiteName:
South Platte River at S.R. 37 near Kersey, CO

Description:
The study site is located at the State Highway 37 bridge crossing the
South Platte River, 2.5 mi downstream of Cache la Poudre River and 1.9 mi
north of Kersey, Colo.  The drainage basin (9,598 sq mi) includes rolling,
irrigated farmland and mountainous areas.  Natural streamflow is affected by
reservoirs, diversions, ground-water withdrawals and return flows.  There is
a sand-bed channel at this location.  A small channel, separated from the main
channel by a large island, merges with the main channel about 100 ft upstream
from the bridge on the right bank (looking downstream). There are three small
islands approximately 250 ft downstream from the bridge, and during low flows,
there are sandbars along the right side of the river downstream from the
bridge.
     The bridge, built in 1958, is 663 ft long, and it has 12 concrete piers
spaced 51 ft apart, centerlines oriented at a 60-degree angle to the roadway
centerline.  During high flow, the piers are aligned with most of the flow,
but during low flows, the piers are at angle to the flow.  This angle is
approximately 0 degrees at the left bank and increases to about 50 degrees on
the right bank.  The majority of the flow is along the left side of the river,
and it is usually contained between the left bank and the 10th pier from the
left bank.  Scour measurements at the first nine piers from the left bank are
reported herein.
     A streamflow-gaging station is located on the left bank downstream of the
bridge.  The range of discharge during data collection was from 1,240 to 6,630
cubic feet per second.  The maximum reported at-pier approach velocity was 5.8
feet per second.  The maximum peak flow for 1984 (May 17) was 9,550 cubic feet
per second.
     Data collection at this site was complicated by the bridge configuation,
accumulation of debris, and flow skewed to the piers.  The bridge deck over-
hangs the upstream edge of the piers by 6.4 ft.  Therefore, the sounding
weights were allowed to drift downstream to measure the scour at the piers.
Large logs and other debris were lodged against the piers on the left side of
the river, making it difficult or sometimes impossible to measure scour depths
near some piers.  Flow skewed to the piers on the right side of the channel
complicated the scour conditions.
     The data reported herein were collected as part of a study of general
scour at bridge crossings and local scour at bridge piers at sites in Colorado
in 1984 (Jarret and Boyle, 1986).  The purpose of the study was to develop and
test guidelines for collecting streambed-scour data at bridges during high
flows.  Equipment and procedures commonly used in the the U.S. Geological
Survey streamflow-gaging program were employed.  A secondary purpose was to
evaluate local-sour-prediction equations.  The four data-collection sites were
selected because record or near-record snow packs were present in the basin
headwaters, and the bridges at the sites did not appear to contract the
main-channel flow.  Estimates of local scour at piers based on the stream
cross-section data collected at the upstream and downstream side of the
bridge are reported here.  Approach depths at piers were computed as the
total depth minus the estimated scour-hole depth.   At-pier approach velocity
and flow skew angle are reported if available.

DescElevREf:
The elevations given are referenced to mean sea level, based on reported
gage heights and a gage datum of 4575.77 ft above mean sea level.
Reference point 1 (yellow paint mark) was located above the fourth pier
(from the left side looking downstream) on the sidewalk.  The bench mark
is a brass tablet set in the concrete sidewalk on left upstream end of
the bridge at a gage elevation of 14.54 ft.


SiteName:
South Platte River at C.R. 87 near Masters, CO

Description:
The study site is located at the County Road 87 bridge crossing the
South Platte River, 1 mile north of Masters and U.S. Highway 34.  The
drainage basin (12,119 sq mi) includes rolling, irrigated farmland and
mountainous areas.  Natural streamflow is affected by reservoirs, diversions,
ground-water withdrawals and return flows.  A diversion dam is located about
1000 ft upsteam of the bridge.  There is a sand-bed channel at this location.
Two tributaries enter the South Platte River at about 100 ft and 25 ft
upstream from the bridge on the right bank.  The majority of the flow is along
the right side of the channel. During low flows, there is a sandbar along the
left side of the channel that extends upstream and downstream from the bridge.
     The bridge, estimated to be at least 40 years old, is 361 ft long, and
it has eight concrete piers spaced 40 ft apart. The piers are perpendicular to
the bridge and generally aligned with the flow. The piers are square nosed
with a width of 0.95 ft and a length of 24 ft. (Sediment samples taken from
the pier-scour holes are identified with a "P".)
     A USGS streamflow-gaging station is located on the right bank downstream
from the bridge.  The range of discharge during data collection was from 1,450
to 8,010 cubic feet per second.  The maximum reported at-pier approach
velocity was 5.2 feet per second.  The maximum peak flow for 1984 (May 18) was
8,220 cubic feet per second.
     Data collection near piers 6, 7, and 8 (numbered from the left bank) was
complicated by accumulated debris and (or) velocities that made positioning
the sounding weights difficult. The depth of scour was measured on either side
of these piers.
     The data reported herein were collected as part of a study of general
scour at bridge crossings and local scour at bridge piers at sites in Colorado
in 1984 (Jarret and Boyle, 1986).  The purpose of the study was to develop and
test guidelines for collecting streambed-scour data at bridges during high
flows.  Equipment and procedures commonly used in the the U.S. Geological
Survey streamflow-gaging program were employed.  A secondary purpose was to
evaluate local-sour-prediction equations.  The four data-collection sites were
selected because record or near-record snow packs were present in the basin
headwaters, and the bridges at the sites did not appear to contract the
main-channel flow.  Estimates of local scour at piers based on the stream
cross-section data collected at the upstream and downstream side of the
bridge are reported here.  Approach depths at piers were computed as the
total depth minus the estimated scour-hole depth.   At-pier approach velocity
and flow skew angle are reported if available.

DescElevREf:
The elevations given are referenced to the gage datum, the elevation of which
was not determined.  The gage altitude from the topographic map was 4450 ft.
Reference point, gage elevation 11.23, was on the top of the H-beam in the
upstream wingwall of the right-bank abutment.  The gage was discontinued
in 1988.


SiteName:
Arkansas River at C.R. 613 near Nepesta, CO

Description:
The study site is located at the County Road 613 bridge crossing the
Arkansas River, 0.98 mile north of Nepesta and U.S. Highway 50.  The
drainage basin (9400+ sq mi) includes rolling, irrigated farmland and
mountainous areas.  Natural streamflow is affected by reservoirs, diversions,
ground-water withdrawals and return flows.  About 60 ft upstream from the
bridge, there is a railroad bridge with two piers that may affect scour at
this site. There is a sand-bed channel at this location. The majority of the
flow is along the left side of the channel. During low flows, there is a
sandbar (about 140 ft wide) in the middle of the channel that extends upstream
and downstream from the bridge.
     The bridge, built in 1905, is 283 ft long, and it has three concrete-
filled steel-cylinder piers spaced 105 ft apart.  The steel cylinders, 4 ft
in diameter, are at each end of the pier, and they are connected by a solid
steel web. Pier length is 21 ft, and pier height is approximately 10-12 ft.
The piers are perpendicular to the bridge and are generally aligned with the
flow.  (Sediment samples taken from pier-scour holes are identified with a
"P".)
     Bridge inspections by Pueblo County officials in 1984 indicated
evidence of scour-related and (or) debris-related deterioration of the left
abutment, pier 1, and pier 2 (numbered from left bank).  Accumulated debris
on the sandbar at pier 2 hampered measurement of scour depths on occasion.
     A streamflow-gaging station operated by the State of Colorado is located
on the right bank about 3 miles upstream from the bridge.  The range of
discharge during data collection was from 360 to 3,690 cubic feet per second.
The maximum reported at-pier approach velocity was 5.4 feet per second.
The maximum peak flow for 1984 (August 22) was 13,600 cubic feet per second.
     The data reported herein were collected as part of a study of general
scour at bridge crossings and local scour at bridge piers at sites in Colorado
in 1984 (Jarret and Boyle, 1986).  The purpose of the study was to develop and
test guidelines for collecting streambed-scour data at bridges during high
flows.  Equipment and procedures commonly used in the the U.S. Geological
Survey streamflow-gaging program were employed.  A secondary purpose was to
evaluate local-sour-prediction equations.  The four data-collection sites were
selected because record or near-record snow packs were present in the basin
headwaters, and the bridges at the sites did not appear to contract the
main-channel flow.  Estimates of local scour at piers based on the stream
cross-section data collected at the upstream and downstream side of the
bridge are reported here.  Approach depths at piers were computed as the
total depth minus the estimated scour-hole depth.   At-pier approach velocity
and flow skew angle are reported if available.

DescElevREf:
The elevations given are referenced to a local datum, the elevation of which
was not determined.  A reference point on the top of the left upstream
wingwall was given an arbitrary elevation of 20.0 ft.


SiteName:
Rio Grande River at U.S.285 near Monte Vista, CO

Description:
The study site is located at the U.S. Highway 285 bridge crossing the
Rio Grande River, 2 mi north of Monte Vista, Colo.  The drainage basin
(1,590 sq mi) includes rolling, irrigated farmland and mountainous areas.
Natural streamflow is affected by reservoirs, diversions, ground-water
withdrawals and return flows.  The majority of the flow is along the left
side of the channel. There is a gravel channel bed at this site. During low
flows, there is a gravel bar along the right bank that extends upstream
and downstream from the bridge.  Also, there is a gravel bar along the left
side of the single pier at the site, and it extends downstream from the
bridge.
     The bridge, built in 1972, is 176 ft long, and one concrete pier is
located at the center of the channel. The pier is 3.25 ft wide at the
bottom tapering to 2 ft wide at the top.  It is 90 ft long at the bottom
tapering to 86.76 ft at the top.  The pier is 13 ft high from the bottom up
to the beam capping the pier. The pier is perpendicular to the bridge and is
generally aligned with the channel. (A sediment sample taken from pier-scour
hole is identified with a "P".)
     A streamflow-gaging station operated by the State of Colorado is located
on the left bank downstream from the bridge.  The range of discharge during
data collection was from 108 to 2,200 cubic feet per second. The maximum
reported at-pier approach velocity was 5.4 feet per second.  The
maximum peak flow for 1984 (May 27) was 3,830 cubic feet per second.
     The data reported herein were collected as part of a study of general
scour at bridge crossings and local scour at bridge piers at sites in Colorado
in 1984 (Jarret and Boyle, 1986).  The purpose of the study was to develop and
test guidelines for collecting streambed-scour data at bridges during high
flows.  Equipment and procedures commonly used in the the U.S. Geological
Survey streamflow-gaging program were employed.  A secondary purpose was to
evaluate local-sour-prediction equations.  The four data-collection sites were
selected because record or near-record snow packs were present in the basin
headwaters, and the bridges at the sites did not appear to contract the
main-channel flow.  Estimates of local scour at piers based on the stream
cross-section data collected at the upstream and downstream side of the
bridge are reported here.  Approach depths at piers were computed as the
total depth minus the estimated scour-hole depth.   At-pier approach velocity
and flow skew angle are reported if available.


Description:
This site is located at the State Route 9 bridge crossing the Leipsic
River at Leipsic, Delaware, 5 miles north of Dover, Delaware.  The arched
bridge, 547 ft long and 29 ft wide, has 12 pile-bent piers.  Three spans are
over the water, with possibly four piers in the flow.  The bridge deck rests
on the pile caps.  Each pile bent includes 5 piles spaced 6 ft apart on
centers.  The piles in the center bents (C2 and C3) have a 3-ft-diameter
concrete collar extending several ft above and below the waterline for
protection from ice.  The Leipsic River is actually an estuary with tidal
flows in both directions.  Net downstream flow is probably a small percentage
of tidal flow.   Any extremely high water is probably associated with storms
causing extremely high tides.  Runoff would probably not contribute much flow.
If the river rises above the tidal banks (several feet above normal high
tide), a very wide floodplain would be inundated.   It is unlikely that the
bridge would be overtopped.

DescElevREf:
BM 4038C 1984 -- assumed elevation 49.990 ft.  Located on approach to bridge
on left bank, downstream side, in concrete curb.


SiteName:
Assawoman Bay at S.R. 54 near Fenwick Island, DE

Description:
This site is located at the State Highway 54 bridge crossing the
waterway connecting Assawoman Bay and Little Assawoman Bay near Fenwick
Island, Delaware.  The waterway is connected to the Atlantic Ocean
10 miles to the north and 8 miles to the south.  The bridge connects the
mainland to the island.  The bridge is 440 ft long and is supported by 10
pile bents spaced 40 ft apart.  The piles extend from the silt and sand
below the mud line, through a concrete strut--located approximately at
the high-water line--to pile caps located just under the bridge structure.
(Pile bents J and K do not have struts.)   Both abutments have
riprap protection.  The flow is tide affected and may reverse directions,
but the predominant flow tends to be from south to north.  The flow may not
reverse when strong winds are coming from the southeast.  (The west side of
the channel is always considered the left edge, regardless of the direction
of flow.)  The bridge is arched and should not be overtopped.  A large
number of small boats use the waterway.

DescElevREf:
The elevations entered here are values from the bridge plans adjusted to
mean sea level (MSL).   Surveys tying the bridge to MSL indicated that the
plan elevations are not MSL elevations.


SiteName:
South Altamaha River at I-95 near Brunswick, GA

Description:
The I-95 crossing of the Altamaha River is located in the Southeastern tip of
Georgia.  It was built in 1970 over a waterway whose flows are tidally
affected but do not normally reverse direction over the tide cycle.
This data set is for the southbound, upstream bridge.  The northbound lane
crosses on a nearly identical, parallel bridge 47 feet downstream.
On January 23, 1990 a passing motorist on the southbound bridge noticed a
pronounced bump and called Georgia Department of Transportation (GDOT).
GDOT inspected the bridge and found a 4-inch sag in the deck at pier 15.
Divers then found a large scour hole at pier 15 and found exposed pile tips
on at least four of the 12 supporting piles.   Emergency contracts were
let to provide additional support for repairs of bents 14,15, & 16 of the
southbound bridge and bent 14 of the northbound bridge.  In subsequent years
additional repairs and countermeasures have been made at additional piers
on the northbound and southbound bridges.
Personnel of the USGS visited the site in February, 1990 to collect detailed
channel geometry, geophysical, and velocity data.   Analyses indicate that
the failure was due to a combination of local scour at pier 15, and the
northward migration of the thalweg since 1970, to a present location
coinciding with pier 15.
This broadly meandering stream has had stable channel boundaries according
to areal photos from 1951 to present.  However, there is a meander cut-off
forming about 2000 feet north of the bridge.  The near channel banks were
about 200 feet apart at the upstream and downstream side of the potential
meander cut-off location in 1951 and 1974 and were about 160 feet apart
in 1988.  The average channel width is about 500 feet.  When this cut-off
occurs, it could place the bridge at increased risk due to scour.

DescElevREf:
Bridge repairs may have damaged or destroyed these RPs.
RP1:  BENT 15 of northbound lane, top of base of pier, which is also the
      pile cap and is near mean high-water elevation, at each of it's four
      corners, Elevation 4.00 ft, MSL (elevation from construction crews)
RP2:  BENT 15.5,  northbound lane, top of base of pier, which is also the
      pile cap and is near mean high-water elevation, at each of it's four
      corners, Elevation 3.50 ft, MSL (elevation from construction crews)
RP3:  handrail on upstream end of left (North) fender.  Top of handrail is
      15.38 ft from levels run from RP2 on 2/11/90.  Temporary staff gage
      was set.


Description:
The State Route 59 bridge crosses the Eel River 3.7 miles north of Clay City,
Clay County, Indiana.  The Conneley ditch bridge, located approximately 1.8
miles south, will act as a relief bridge for very large floods.  No scour
data has been obtained for this relief bridge. Both upstream overbanks are
tilled with some woods between the fields and the channel.  The downstream
right overbank is wooded for several hundred ft downstream of the bridge.
The downstream left overbank is mostly tilled with some trees and cabins
between the field and channel. At low flows, the channel banks are steep and
relatively high.  Sloughing indicates that the banks are actively eroding.

DescElevREf:
BM:  Unlabeled INDOT bronze tablet on the downstream left end of the bridge,
elevation = 562.54 ft.
RP-1:  Mark on guard rail at bridge station 108, on the upstream side of the
bridge, elevation = 565.33 ft.
RP-2:  Mark on the guard rail at bridge station 108, on the downstream side of
the bridge, elevation = 565.33 ft.


Description:
This site is at the the State Route 163 bridge crossing the Wabash River on
the east side of the town of Clinton.   The Wabash River is the county line
between Vermillion County on the west and Parke County on the east. The mile
point is referenced to the Indiana-Illinois State line.
The left bank is leveed both upstream and downstream from the bridge,
while the right bank has a natural hillside that has been terraced by
construction.  The left overbank is wooded upstream and downstream from the
bridge.  The right bank has some trees and brush, and remains steep for
several hundred feet downstream from the bridge.  Upstream from the bridge,
the right bank levels off where there is a community park and boat launch.
Approximately 1000 ft upstream from the S.R. 163 bridge, there is a
railroad bridge.
Only piers 6, 7, and 8 are in the channel.

DescElevREf:
INDOT bronze tablet #VERM C-29 at the northwest end of the bridge (upstream
right end), elevation = 495.325 ft.
The bridge has a wire-weight gage on the upstream side.  The elevation of the
check bar is 499.24 ft at a reading of 46.822 ft.


SiteName:
White River at S.R. 157 at Worthington, IN

Description:
This site is located about one mile southeast of the town of Worthington, and
about half a mile south of the confluence with the Eel River.  The site has a
steep right bank that is wooded.  The left overbank is low-lying farm fields
with a strip of woods between the fields and the river.  The road embankment
is low enough left (east) of the bridge that during high flows a significant
amount of flow will bypass the bridge.  The measurement on 1-1-93 had
43,400 cubic ft per second (cfs) in the bridge opening, but the total
discharge is estimated at 64,000 cfs.  If this estimate is accurate, the
flood on 1-3-93 had a 10-year recurrence interval.

DescElevREf:
INDOT bronze tablet on the northwest end (upstream right) of the bridge,
elevation = 528.06 ft.
RP-1:  Mark on the guard rail at bridge station 622 on the upstream side of
the bridge, elevation = 530.02 ft.
RP-2:  Mark on the guard rail at bridge station 622 on the downstream side of
the bridge, elevation = 530.04 ft.


SiteName:
Red River at S.R. 3032 near Shreveport, LA, E.B.

Description:
The S.R. 3032 bridge over the Red River is referred to as the Barksdale
Bridge and connects Shreveport and Bossier City.  The flood plain is of
low relief with numerous oxbow lakes.  However, at the bridge the flood
plain is narrowed by levees on both sides.  The site consists of two bridges--
the upstream bridge is the westbound lane of S.R. 3032, and the downstream
bridge is the eastbound lane of S.R. 3032.  The river is straight for more
than 10 channel widths upstream and downstream from this bridge.
No bed-material samples were available for this site, so samples collected
during the same event at Coushatta, located about 50 miles downstream, will be
used.
                         Bed-Material Sample Numbers:
                   Left side          Center         Right side
Above bridge        8703               8704            8705
Below bridge        8706               8707            8708
This entry is for the downstream or eastbound bridge.
The stage and discharge hydrographs are from the Corps of Engineers gage at
Shreveport, which is located about 2 miles upstream from the bridge.  The peak
stages are at the bridge.  The drainage area is from the Shreveport gage.
Approach and exit sections were surveyed on 5-18-90 using a Raytheon
fathometer.  The survey was from tree-line to tree-line.  However,
these cross sections appear to be 8-10 ft higher than the cross sections
collected at the bridge and low-water cross sections taken from 1968-69
and 1980-81 hydrographic surveys published by the U.S. Army Corps of
Engineers, New Orleans District.  However, the elevation of the low-water
sections did agree reasonably well with the ambient bed elevation of the
cross sections collected at the bridge during the flood.  Because of
these discrepencies associated with the elevation of the approach and exit
sections, no contraction scour is reported based on these data.  The shape
of the approach and exit sections were used to assist in the determination
of the ambient bed for the local scour reported herein.  The approach and
exit sections are included as part of this data set because of their use in
determining the ambient bed, however, their usefulness for other purposes
is questionable based on the information presented above.
This is the downstream bridge of two parallel bridges.  The velocities
reported with the local-scour measurement are from measurements made
at the upstream bridge.  The piers at the two bridges are aligned,
therefore the actual approach velocity for the downstream bridge may be less
than the values reported, because of the effect of the piers of the upstream
bridge.

DescElevREf:
R.P. #1 set on upstream (westbound) bridge, on upstream side of bridge,
chiseled square on top of handrail 40 ft west (rt) of centerline of Pier #4,
which is at Hwy Plans sta 103+48, 1340 ft from left abutment.
Elevation for R.P. #1 was determined by taping up:
  Finished grade centerline elevation at piers 3 and 4 = 226.4 ft (msl)
  Taped up centerline to wheel guard (0.75) to concrete handrail(2.05)
Elevation at R.P. #1 = 229.2 = 226.4 + 0.75 + 2.05


SiteName:
Pearl River at eastbound U.S. 98 near Columbia, MS

Description:
This is a 696-ft-long bridge crossing the Pearl River about 1.5 mi southwest
of Columbia at river mile 137.8. This entry is for the eastbound lanes, which
are downstream from the westbound lanes. The bridge has four piers (pier nos.
4-7) within the low-water channel and pier no. 8 near the right (west) edge of
the low-water channel. Pier nos. 3-6 consist of two rectangular, vertically
tapered piers with a connecting web wall. Pier nos. 2 and 7-9 consist of two
rectangular, vertically tapered piers with no connecting web wall. The
upstream side of this bridge is 78 ft downstream from the upstream side of the
westbound-lane bridge. The bridge is in a 190-ft-long vertical curve with
0.35% approach grades. The spill-through slopes at the abutments are earthen.
Riprap is scatterred on the left bank through the bridge opening and is
scattered in the vicinity of pier no. 4, which should have an effect
on the local scour.
   The upstream left (east) bank has experienced lateral erosion in recent
years. The bridge crossing is in a channel reach in a transition between a
125-degree bend about 1,700 ft upstream and a 145-degree bend about 1,100 ft
downstream from the bridge. In an effort to control the bank erosion on
the left bank, five flow deflectors were constructed along the left bank in
1985-86 from the bridge to about 1,600 ft upstream.
   Scour data were collected during high and low flows using a fathometer. The
flow velocities approaching the bridge piers were estimated using the
velocities measured at the upstream side of the upstream bridge, about 78 ft
upstream of this bridge. Therefore, the change in flow velocity that may have
occurred between the upstream bridge and the upstream side of this downstream
bridge is not accountable.
   On October 4-9, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected:

  Cross    Distance
Section  Upstream  Sample   Comments
    1     180 ft     1     Represents right part of chanel begin near station 8180.
    1     180 ft     2     Represents left part of channel end near station 8180. 
    2   1,200 ft     3     Within main flow of low-water channel, from tip of 4th 
                           jetty upstream to about 100 ft right.
    2   1,200 ft     4     Right part of channel, 175ft from tip of 4th jetty to RWE
    2   1,200 ft     5     Near upstream end of 4th jetty.
    3   2,100 ft     6     At upstream end of sand/gravel bar, all samples here
                           combined.  

   No bed samples were obtained at the piers due to debris, etc. Based on rod
probings at the piers, the material at the base of the piers is thought to be
mostly gravel with some sand and debris. Also, soil borings by the MDOT
indicate gravel. Therefore, bed sample no. 6 was selected as representative.

DescElevREf:
Wire-weight gage attached to the upstream side of the upstream bridge. Check-
bar reading at 61.00 ft (elev. 176.81 ft (NGVD)).
Centerline elevation of downstream bridge at the left (east) abutment
(Elev. 155.46 ft).
BM-6.-- Chiseled square on downstream streamward corner of bridge seat of left
(east) abutment (Elev. 151.47 ft).


SiteName:
Pearl River at westbound U.S. 98 near Columbia, MS

Description:
This is a 785-ft-long bridge crossing the Pearl River about 1.5 mile
southwest of Columbia at river mile 137.8. This entry is for the westbound
lanes, which are upstream from the eastbound lanes. The bridge has three
4-ft-diameter pier bents (Nos. 4-6) within the low-water channel supporting
the main span over the channel and five interior double-18x18-inch-pile bents
(Nos. 2-3 & 7-9) supporting the approach spans on the flood plain. The bridge
is in a 680-ft-long vertical curve with 4.0% approach grades. A 150-ft-long
spur dike is located at the right (west) abutment. The left (east) bank is
covered with riprap through the bridge. The spill-through abutments are paved
under the bridge but are not paved on the upstream slope.
   The upstream left (east) bank has experienced lateral erosion in recent
years. The bridge crossing is in a channel reach in a transition between a
125-degree bend about 1,600 ft upstream and a 145-degree bend about 1,200 ft
downstream of the bridge. In an effort to control the bank erosion on the left
bank, five flow deflectors were constructed in 1985-86 along the left bank
from the bridge to about 1500 ft upstream.
   Scour data were collected during high and low flows using a fathometer. The
flow velocities approaching the bridge piers were determined from velocity
soundings during discharge measurements at the upstream side of the bridge.
   On October 4-9, 1991, bed samples were collected from the main channel at
selected intervals along three channel cross sections. Individual samples with
similiar characteristics were combined for gradation analyses. The following
is a brief description of the bed samples collected :

Cross    Distance
Section  Upstream  Sample   Comments
    1     100 ft     1     Represents right part of chanel begin near station 8180.
    1     100 ft     2     Represents left part of channel end near station 8180. 
    2   1,100 ft     3     Within main flow of low-water channel, from tip of 4th 
                           jetty upstream to about 100 ft right.
    2   1,100 ft     4     Right part of channel, 175ft from tip of 4th jetty to RWE
    2   1,100 ft     5     Near upstream end of 4th jetty.
    3   2,000 ft     6     At upstream end of sand/gravel bar, all samples here
                           combined.  

   No bed samples were obtained at the piers due to debris, etc. Based on rod
probings at the piers, the material at the base of the piers is thought to be
mostly gravel with some sand and debris. Also, soil borings by the MDOT
indicate gravel is present. Therefore, bed sample no. 6 is thought to be
most representative for the bed material at the base of pier nos. 4-6.
   The International Standard ISO 9195, "Liquid flow measurement in open
channels -Sampling and analysis of gravel-bed material", prepared by Technical
Committee ISO/TC 113 suggests sampling at the upstream end of gravel bars. The
coarse material is associated with the channel-forming processes and sediment^
transport. Therefore sample no. 6 was selected as the most representative.


SiteName:
Clarks Fork Yellowstone River near Bridger, MT

Description:
The site is 2 miles south of Bridger, Montana.  The bridge spans the main
channel and has no scour countermeasures or upstream or downstream influ-
ences.  The USGS gaging station "Clark Fork Yellowstone River near Belfry,
MT" (06207500) is about 25 river miles upstream from the bridge. The USGS
gaging station "Clarks Fork Yellowstone River at Edgar, MT", (06208500), is
about 24 river miles downstream from the bridge.  Selected flood-frequency
estimates for the site using USGS stations 06207500 and 06208500 result in
a 100-year peak estimate (Q100) of 13,800 cfs and a 500-year peak (Q500) of
15,900 cfs. The watershed is presumed to be fairly stable in terms of sediment
yield and channel-change potential.  An inspection of historic rating curves
for the two gages showed no more than a few tenths of a foot shift per year
and no consistent trend towards scouring or filling over the long term. The
bed-material-sample transect was located within the bridge opening and
because material was coarse, the sampling method used was a random-count
procedure performed by hand in the field.  Although live-bed scour was
presumed for a level-2 analysis, critical-velocity and shear-stress
calculations showed only marginal conditions for live-bed scour at Q100 and
Q500.  Clear-water scour was thus presumed for the measurements reported here,
because armoring was believed to be a factor and actual flows were less than
those (Q100 and Q500) used in the level-2 analysis.  Determination of scour
variables first required adjusting the horizontal stationing of the bridge for
the 25-degree skewness to flow.  The adjusted section was then plotted and
scour variables measured.

DescElevREf:
Benchmark is US Coast and Geodetic Survey (USCGS) monument (C564) having
elevation 3670.388 from datum of 1988 and located on right upstream concrete
abutment.  Datum used on Montana Department of Transportation (MDT) drawings
does not equal USCGS datum described above.  The MDT datum is estimated to be
about 3 feet lower (+/- 0.5 ft) than USCGS.  The USCGS datum is used through-
out this file.  Elevations for pier and footings were estimated using USCGS
datum and dimensions indicated on the MDT drawings.


SiteName:
Gallatin River at U.S. 191 near Gallatin Gateway, MT

Description:
The site is 5 miles south of Gallatin Gateway, Montana.  The bridge is at
the mouth of the Gallatin canyon, where the alluvial characteristics of the
stream change rather abruptly.  Upstream from the bridge, the river meanders
through the canyon in a high-elevation alpine environment, is a sequence of
pools and riffles, and is neither braided nor anabranched.  Downstream from
the bridge, the river exits the canyon and enters the Gallatin valley, where
the river becomes generally braided and anabranched.  Annual-peak-discharge
data were collected for 60 years at the USGS streamflow-gaging station
"Gallatin River near Gallatin Gateway,  Montana" (06043500).  Selected flood-
frequency data (personal comm. Robert J. Omang, 1992) for the site are as
follows:

Station Number   Drainage Area    100-year    500-year
                   (Sq. Mi.)        (cfs)      (cfs)
 06043500            825           10,700      12,700

The largest recorded peak discharge at the gage was 9,270 cubic feet per sec-
ond (cfs) in 1971.  Peak discharges of similar magnitude also occurred in
1970 (9,240 cfs) and 1974 (9,100 cfs).  The 100-year and 500-year peak disch-
arges at the U.S. 191 bridge were assumed to equal the values at the gage
because the two locations are in close proximity to one another.  Although
the watershed has been subjected to recent fires and land-use changes, their
overall effect on basin sediment yields is believed to be relatively minor.
The watershed is thus presumed to be fairly stable in terms of sediment yield
and channel-change potential.  The USGS gaging-station history describes the
stream in the vicinity of the gage (06043500) as "very stable".  Rating-curve
shifts were found to be on the order of a few tenths of a foot.  Channel-
geometry data for this file are referenced from left edge of water (LEW) to
right edge of water (REW)--thus, pier stationing needs to be used to reference
sections to each other.  Because of the high degree of armoring, the surface
layer of the streambed is believed to be most representative for evaluating
scour.  Gradation of the material was estimated using a random-count proced-
ure, and the sample was obtained within an area close to the downstream face
of the bridge opening.  Based on field observations, scour measurements, rat-
ing-curve shifts, and a level-2 analysis, general scour and contraction scour
do not appear to be a factor at the site.  Although level-2 calculations
indicate a potential for abutment scour, actual scour would probably be less
than predicted by the Froelich equation (generally recognized to estimate
abutment scour conservatively high) and would require discharge much greater
than what has been observed during the project to date.

DescElevREf:
Benchmark is US Coast and Geodetic Survey monument number G160 (1960),
equal to elevation 5,129.271.


SiteName:
Yellowstone River at U.S. 89 near Emigrant, MT

Description:
The site is located 11 miles southwest of Emigrant, Montana and drains
an area of about 2,844 square miles.  Annual-peak-discharge data were
collected for 42 years at the USGS streamflow-gaging station
"Yellowstone River at Corwin Springs, Montana" (06191500).  The
largest recorded peak discharge at the gage was 32,000 cubic feet per
second (cfs) in 1918.  The next two largest peak discharges occurred
in 1974 (30,900 cfs) and 1911 (25,800 cfs).  Selected flood-frequency
data for the gage (Omang, 1992), adjusted for drainage area, give
100-year and 500-year peak discharge estimates at the bridge equal to
31,900 cfs and 35,700 cfs, respectively.  Bed material was sampled
within the bridge opening and because material was coarse and armoring
was observed, the sampling method used was a random-count procedure
performed by hand in the field.  Although the watershed has been
subject to recent fires and land-use changes, their overall effect on
basin sediment yields is believed to be relatively minor.  The
watershed is thus presumed to be fairly stable in terms of sediment
yield and channel-change potential.  The station history for the USGS
gage (06191500) indicates only minor shifts, generally on the order of
a tenth of a foot or less.  An example of channel stability during
high flows is demonstrated by a rating, which has been used at the
gage since 1979.  Runoff measured at the gage for the period
1979-present (1994) included three floods that had peaks ranging from 21,900
cfs to 24,700 cfs (69 to 77 percent of 100-year flood peak).  Although
the gage is about 13 miles upstream from the bridge, channel stability
at the two locations is presumed to be similar.  Measured scour holes
were observed to change over time, however, the change was considered
minor and thus, clear-water scour was presumed to occur during
measurements.  In performing level-2 analyses at the 100-year and
500-year floods, shear-stress calculations for the streambed
indicated that live-bed scour was only marginally more likely to
occur, compared to clear-water scour.  In contrast, comparison of
critical and mean velocities indicated clear-water scour conditions.
Taking into account other factors, including the presence of armoring
at the site and the fact that only minor rating shifts have occurred
at the USGS gage, lead to the conclusion that clear-water scour
predominates at the site.  The presence of riprap and greater main-
channel flow depth on the left side indicates that the left bridge
opening has been subjected to some form of abutment scour.  A compar-
ison of cross sections surveyed in 1992 and 1993 and at the time of
construction confirm that about 2 feet of abutment scour has occurred.
Left abutment scour is probably caused by flow impingement, rather
than by the factors accounted for in prediction equations, such as
return of overbank flood-plain flow to the main channel.  Based on a
comparison of sections, contraction scour was found to not be a factor.
Data describing piers, abutments, and other horizontal and vertical features
are based on USGS survey work for measuring on-site scour, to perform a
level-2 analysis, and to perform beta-level verification of the BRISTARS
model using scour-related data from the site (planned).

DescElevREf:
Benchmark is US Coast and Geodetic Survey (USCGS) monument number
Z565 (1988 datum) equal to elevation 4964.63, located on right
upstream corner of bridge and set in concrete walkway.


SiteName:
Badger Creek at U.S. 89 near Browning, MT

Description:
The bridge site is 15 miles southeast of Browning, Montana.
Drainge area at the site is 239 square miles, with headwaters
draining from the Rocky Mountain front.  The main channel of Badger
Creek is perched in relation to the right flood plain, and the main
channel has a a high degree of lateral instability.  There is a
significant right overbank flood plain and the majority of flood flows
are conveyed by road overtopping to the right of the bridge.  A USGS
streamflow-gaging station (06092500) is located several river miles
upstream of the bridge site and has a drainage area of 133 square miles.
Annual-peak-discharge data were collected for 23 years at the USGS
streamflow-gaging station "Badger Creek near Browning, Montana" (06092500).
As reported by Omang (1992), selected flood-frequency data for the site
give 100-year and 500-year peak discharge estimates equal to 13,000 cfs
and 26,500 cfs, respectively.  The largest recorded peak discharge at
the gage was 49,700 cfs on June 8, 1964.  The next two largest peak
discharges occurred in 1953 (4,220 cfs) and 1970 (3,670 cfs).
Although drainage area at the site is greater than at the gage, the
area upstream from the gage contributes most to producing flood flows--
thus, the 100-year and 500-year peak discharges are presumed to apply at the
bridge site.  The streambed is composed of relatively coarse material,
however, the bed is not armored and is therefore considered unstable.
Bed-material sample used in the sieve analysis (performed at the
Materials Bureau of MDT) was from the bridge opening, between the
upstream and downstream face.  Two core logs shown on MDT drawing no.
7043 describe material underlying pier footings and abutments as being
composed of dense sandy gravel with traces of clay. A third core log
describes foundation material as dense gravelly sand with cobbles and
some trace of clay.  Drill holes ranged in depth from 41 feet to about
76 feet below the surface of the streambed.  The gaging-station
history at the USGS streamflow-gaging station "Badger Creek below Four
Horns Canal near Browning, Montana" (06093200) indicated that "the
channel is often unstable, especially during high flows."  This gaging
station was used instead of station 06092500 for interpreting
stability because channel control occurs, whereas the control for
station 06093200 is a diversion dam structure.  Inspection of
stage-discharge rating curves for the period 1973 to the present (1994)
indicate a trend towards channel aggradation (filling) at high flows.
Relative channel stability was also evaluated using incipient motion
analysis.  Hydraulic results from WSPRO, coupled with gradation curve
data and shear stress calculations for the stream bed indicate channel
instability at both the 100-year and 500-year floods.  Because
calculations indicate that live-bed scour occurs, development of an
armor layer is presumed to be unlikely.  There is evidence of about
2.5 ft of scour at the left and right abutments.  A comparison of
bridge sections for different dates show that contraction scour (to a
maximum of about 0.5 ft) may occur.  If the vertical changes
(excluding local scour at piers and abutments) were accumulated
laterally across the section, however, the net change would be zero.

DescElevREf:
Reference mark number 1 (RM1) is chiseled "X" on left upstream (southwest)
concrete abutment wingwall set to elevation 99.99 feet.


SiteName:
Otselic River at S.R. 23 at Cincinnatus, NY

Description:
This site is located at the State Route 23 bridge crossing the Otselic
River at Cincinnatus, New York.  The bridge, 187 ft long and 40 ft wide with
one pier, is 0.5 mile downstream from a USGS streamflow gage.  The pier
footing has been undermined by scour, but the bridge is supported by pilings.
A 30-degree angle between the pier and flow increases the tendency of the
streambed to scour and has resulted in scour along the entire length of the
pier. The deepest scour is 10 to 25 ft downstream from the pier nose.
     Clear-water scour is common at this site.  Multiple high flows have
progressively deepened the local-scour hole.  Each additional scour event is
being analyzed separately for the New York study. However for the USGS
national scour study, the "total" local scour is the depth of scour that the
earlier high flows may have produced if the flow duration was sufficient to
produce an equilibrium scour depth.  The local-scour value listed in this
data base for the 1990 high flow includes the previous local scour from
earlier high flows.
     General or contraction scour may have lowered the ambient bed 1-2 ft from
the 1027 ft elevation listed in the bridge plans.  The USGS stage-discharge
relation can account for 0.3 ft.  Contraction scour is insignificant based on
approach, bridge, and exit cross sections.
     The streambed is armored by gravel.  Occassional mining in the stream
about 0.5 mile upstream from the bridge at point bars does not appear to
be degrading the thalweg. However, the thalweg may be migrating into the
local-scour hole because the hole is now the lowest point in the channel.
     Bed-material samples were collected in a shallow area of the channel near
the bridge.  The D16, D50, and D84 were analyzed.  The D90 or D95 were not
analyzed because of the accuracy of the limited data set.
     Debris and high flow in 1993 lowered the channel near station 120 to 1019
ft msl, but the debris prevented additional local scour at the nose of the
pier.
     The local-scour hole does not refill after each high flow.
     Local-scour depth is based on USGS measurements, although New York
State Department of Transportation (NYSDOT) measurements are considered in the
analysis.  The 1988 NYSDOT ambient bed is questionable because it is 1.3 ft
higher than the 1989 USGS measurement, and no significant high flow occurred.
A USGS measurement in 1989 found scour hole at 1022.7 ft at the upstream
side of the bridge (ussb).  Because ambient bed is 1025.5 ft, 2.8 ft of local
scour is calculated. The location of maximum scour was not measured in 1989,
based on later data that show the deepest scour located 10-25 ft downstream
from the pier nose.  High flows in 1983, 1984, and 1986 are assumed to have
contributed to the scour measured in 1989.
     High flow in 1990 lowered the scour hole to 1020.6 at ussb and 1019.9
25 ft downstream.  The ambient bed was lowered 0.4 ft, therefore, local scour
is calculated to be 5.2 ft under the bridge (1025.1-1019.9).
     In the New York study, each high flow is analyzed separately.  Because
the elevation of the scour hole under the bridge is unknown before the 1990
high flow, 1.7 ft of local scour is attributed to the 1990 high flow based on
ussb data (scour hole was 2.1 ft deeper and ambient bed was 0.4 ft lower in
1991 than in 1990).

DescElevREf:
USSB: RM = Chiseled X in top of upstream bolt at base of first guardrail at LE
                         of bridge.  ELEVATION = 50.00 ft (local).
      RP = Chiseled X in top of guardrail post at station 49.
                         ELEVATION = 53.26 ft (local).
                         Bottom of pier footing = 1022.0 ft MSL (bridge plans)
                         RP = station 49
                         LE footing   = station 93, LE pier at station 94
                         RE footing  = station 99, RE pier at station 98
DSSB: RP = Chiseled X in top of guardrail post across from RP at USSB.
                         ELEVATION = 53.27 ft (local)
APPR: RP = Lag bolt in 6-inch elm tree 200 ft upstream, left bank.
                         ELEVATION = 41.19 ft.
EXIT: RP  =  Lag bolt in 8-inch willow tree 200 ft downstream, left bank.
                         ELEVATION = 40.70 ft (local)


SiteName:
Chemung River at S.R. 427 at Chemung, NY

Description:
The site is located at the State Road 427 bridge crossing the Chemung
River at Chemung, New York.  The bridge, 798 ft long and 47 ft wide with six
concrete piers, is about 100 ft downstream from a USGS streamflow gage.
A spur dike is located at the left abutment.
     Clear-water scour is common at this site.  High flow in 1972 undermined
piers 2-6 and piles prevented a bridge collapse.  Streambed material placed
around piers in 1972-73 was eroded by high flow in 1975. It is uncertain
whether riprap or bed material was placed at pier 1.  Additional scour
occurred during high flow in 1979.  Riprap was placed at piers 1-2 (main
channel) in 1988.  Regulation has reduced high flows since 1979, but the scour
hole at pier 1 has widened.
     The scour data are entered for the date on which they were collected,
although the scour and hydraulics are associated with the previous
flood (scour measured from the 1980 data is associated with the 1979 flood).
The 1979 scour is analyzed separately for the New York study. However, for the
USGS national scour study the "total" local scour is the depth of scour that
earlier high flows may have produced if the flow duration was sufficient to
produce an equilibrium scour depth.  Therefore, the local scour listed for
1979 includes the local scour during the 1975 high flow.  In clear-water scour
conditions, high-flow events leave remnant scour holes that subsequent high-
flow events progressively deepen.  The local scour reported here is referenced
to concurrent ambient-bed level (equilibrium conditions assumed).  A separate
analysis of the progressive increase in scour from one event to the next is
being made by U.S. Geological Survey personnel in New York.
     Significant contraction scour or general scour occurred in 1972, however,
measured data are incomplete and are not included in this database.  The
USGS stage-discharge relation indicated filling of the low-water control
followed by a gradual return to pre-flood elevations.
     The streambed is armored by gravel.  Bed-material samples were collected
in a shallow area of the channel near the bridge.  The D90 and D95 were not
analyzed because of the accuracy of the limited data set.

DescElevREf:
USSB: RM = USGS tablet, right abutment.  ELEVATION = 32.15 ft (gage datum).
           gage datum = 778.63 ft.
      RP = Wire-weight gage at station 595.  ELEVATION = 35.57 ft (gage datum)
      Left abutment   = station -25
      LE pier 6 = station 86
      RE pier 6 = station 89
      LE pier 5 = station 201
      RE pier 5 = station 204
      LE pier 4 = station 315
      RE pier 4 = station 318
      LE pier 3 = station 429
      RE pier 3 = station 432
      LE pier 2 = station 544
      RE pier 2 = station 547
      LE pier 1 = station 658
      RE pier 1 = station 661
      Right abutment= station 773
DSSB: RP = Chiseled square (lower section of slant) at station 630.


SiteName:
Schoharie Creek at S.R. 30 at Middleburg, NY

Description:
This site is located at the State Road 30 bridge crossing Schoharie Creek
in Middleburg, New York.  The bridge, 356 ft long and 43 ft wide, has three
piers.  Piers 1 and 2 are in the main flow channel and have exposed footings.
Clear-water scour is common at this site.  Local-scour holes do not refill
after high flows.  The local-scour depth is based on the ambient bed.  Flow
is partially regulated by Schoharie reservoir, which has a drainage area
of 315 square miles.  Except for periods of spilling, the reservoir impounds
water for the New York City water supply.  Flow begins to bypass the
bridge along the left bank at about 50,000 cfs (recurrence interval of about
25 years).
    Only one local-scour depth is listed for each pier.  However, the stream
may not have reached equilibrium local-scour depth because of the gravel armor
layer.  If additional local scour occurs, the scour will be added to the
present scour assuming the ambient bed does not change (USGS national scour
study).  In the New York study, additional local scour is to be analyzed
separately.
     About 1.3 ft of contraction scour appears to have occurred in 1987 based
on the bridge thalweg elevation minus the exit thalweg elevation.

DescElevREf:
USSB: RM = Lag bolt at station 354, left abutment ELEVATION = 637.59 ft msl
      RP  = Wire weight gage at station 45, checkbar = 640.91 ft msl.
DSSB: RP = Beveled corner of concrete sidewalk across from WWG at station 308.
                         ELEVATION = 638.76 ft msl.
APPR: RP = Staple in upstream side of 30-inch tree, 300 ft upstream, rght bank
                         ELEVATION = 628.58 ft msl.
EXIT: RP = Staple in upstream side of 36-inch tree, 350 ft downstream, right bank, 
           streamward of pole #4 and light #7. 
                         ELEVATION = 627.14 ft msl.


SiteName:
Susquehanna River at C.R. 314 at Conklin, NY

Description:
The site is located at the County Road 314 bridge crossing the
Susquehanna River at Conklin, New York.  The bridge, 642 ft long and 34 ft
wide with four piers, is 500 ft downstream from a USGS streamflow gage. Piers
3 and 4 (center and right) have footings exposed.  The footing at pier 4 is
exposed by 3 ft--however, it was constructed at an elevation 3 ft higher than
pier 3.  The footing at pier 2 is not exposed, but it is at an elevation 1.5
ft lower than pier 3.
     High flows in 1977, 1979, 1983, 1986 may have added to the local scour
measured at piers 2-4 in 1989-92. It is unknown at this time why the greatest
local scour is measured at pier 4 where flows are slower and shallower than at
piers 2-3.  Perhaps the bed material is coarser at piers 2-3 than at pier 4.
     The streambed is armored by gravel. Clear-water scour is common at this
site.  Multiple high flows may have progressively deepened the local-scour
hole, but hydraulic data for the highest flow is analyzed because the amount
of scour caused by each flow is unknown.  The local-scour depth is
based on the ambient bed and changes in elevation of the scour hole.
Contraction and general scour are insignificant.
     Bed-material samples were collected in a shallow area of the channel near
the bridge.  The D16, D50, and D84 were analyzed.  The D90 or D95 were not
analyzed because of the accuracy of the limited data.
     Local-scour holes do not refill after each high flow.  A minor debris
pile may be "armoring" the scour hole at pier 4 in 1993.

DescElevREf:
USSB: RM = Tablet set in left abutment.  ELEVATION = 900.92 ft
      RP = Wire-weight gage at station 294.  ELEVATION = 893.57 ft
      Right abutment = station 634  RE pier   = station 246
      RE pier  = station 507             LE pier    = station 241
      LE pier  = station 502             RE pier   = station 116
      RE pier  = station 377             LE pier    = station 112
      LE pier  = station 372             Left abutment = station   0
      RP       = station 294
DSSB: RP = Chiseled square on downstream right corner of guardrail-support
            foot plate at station 276, across from WWG.  ELEVATION = 891.83 ft
APPR: RP = Lag bolt in downstream side of maple tree 650 ft upstream, 160 ft
            upstream of gage, 1.5 ft LSD, left bank.  Tree is fourth cluster 
            of trees upstream of gage.  ELEVATION = 11.79 ft (gage datum).
EXIT: RP = Lagbolt in streamward side of upstream-most 3-ft maple tree in 
           cluster of three trees, 1 ft LSD, left bank.  Bolt approx. 700 ft 
           downstream of bridge and 30 ft upstream of culvert under railroad tracks.
           ELEVATION = 11.63 ft (gage datum).
           RP =  Lag bolt on upstream side of 1.5 ft maple tree, 5 ft landward and
           5 ft downstream of first RP.  Bolt in cluster of two trees, 3 ft 
           LSD.  ELEVATION = 14.90 ft (gage datum).


SiteName:
Genesee River at Bailey Road at Portageville, NY

Description:
The site is at the Bailey Road bridge crossing the Genesee River
at Portageville, New York.  The bridge, 400 ft long and 34 ft wide with
three piers, is 2 miles upstream from a USGS streamflow gage.  Pier 1
(on left side when looking downstream) is out of the water except during
very high flows.  The piers are founded on bedrock, although the bridge plans
show a 5-10 ft layer of gravel above the bedrock at the right pier.  Bedrock
is visible at pier 2, and a gravel bar extends along the right bank.  Stream
velocity is concentrated toward the left half of the channel because of a
bend 500-1000 ft upstream.  Clear-water scour is common here.  Local scour is
based on a 1988 inspection and 1986-88 New York State Department of
Transportation (NYSDOT) inspections because the deepest scour is about 5 ft
downstream from pier 3.  The location of the scour hole may be affected by
the large sharp-nosed pier producing vorticies at the break in pier shape.
Reference for the scour depth is the ambient bed.
     General scour is minimal at the USGS site because of bedrock outcrops in
the channel. Significant contraction scour (greater than 3 ft) occurred in
1989 from a large debris jam at pier 2 that blocked one third of the bridge
opening.  However, insufficient data are available to include a contraction
scour measurement.  Hydraulic analysis of debris blockage showed an 11+ ft
per second average flow velocity, comparable to velocities during the 1972
flood (recurrence interval 100+ years) that destroyed the previous bridge.
There was about 5 ft of aggradation in the bridge opening from 1989-1991,
possibly from bed material that was mobilized in the bridge reach in 1989.
The 1992 inspection showed minor degradation as the channel began to
restabilize.
    Bed material samples were collected in a shallow area near the right bank.
The D16, D50, and D84 were analyzed, but the D90 and D95 were not analyzed
because of the accuracy of the limited data set.
     There is an ample supply of debris coming from Letchworth State Park.
     Local scour is assumed to have occurred during the greatest flow
previous to the 1988 NYSDOT measurement--6/18/84 (recurrence interval of
about 10 years).
     Local scour was observed only at pier 3.

DescElevREf:
USSB:  RM = Chiseled square on left abutment at station 0.  ELEVATION = 1152
                           ft.  Top of pier footing = 1102 ft msl.
             RP = 2 file marks on 2nd handrail at station 235.  ELEVATION = 1143.49 ft.
                           Left abutment  = station 0.
                           LE pier = station 96.
                           RE pier = station 100.
                           LE pier = station 196.
                           RE pier = station 202.
                           RP      = station 235.
                           LE pier = station 296.
                           RE pier = station 302.
                           Right abutment = station 400.
DSSB:  RP = 2 file marks on 2nd handrail at station 235. ELEVATION = 1143.67 ft.
APPR:  RP = Lag bolt in large sycamore tree 354 ft upstream, overhanging water on 
       left bank. ELEVATION = 1112.05 ft.  
             Lag bolt in pole, ELEVATION = 1113.13 ft. 
(EXIT=bolts in cottonwood, left bank1104.54 ft and 1112.83 ft).


SiteName:
Delaware River at Route 6 at Port Jervis, NY

Description:
The site is located at the Route 6 bridge crossing the Delaware River in
Port Jervis, New York.  The bridge, 649 ft long and 58 ft wide with one
pier, is 250 ft upstream from a USGS streamflow gage.  There is significant
regulation of flow by upstream reservoirs.  There is no general scour based
on the USGS gage rating, and there is no apparent contraction scour.
The streambed is armored by gravel. The local-scour hole does not
refill after high flow.  Clear-water scour is common.  Local scour occurred
before the initial scour measurements.  Therefore, the 1955 flood (peak of
record with a recurrence interval (RI) of 100+ years) is assumed to have
produced all the scour.  However, high flows during 1942 (RI about 30 years),
1940 (RI about 12 years), 1973 (RI about 10 years), and 1986 (RI about 8 years
could have contributed to the scour measured from 1986-1992.  Local scour
is based on the ambient bed and is an average of measurements 1989, 1991, and
1992.  The cross sections at the downstream side of the bridge show little
change in elevation from 1942-1989.
     Bed-material samples were collected in a shallow area of the channel near
the bridge.  The D16, D50, and D84 were analyzed.  The D90 and D95 were not
analyzed because of the accuracy of the limited data set.
     Significant ice jams may occur during severe winters and low flow.

DescElevREf:
USSB: RP = Top vertical railing support at station #57, painted yellow.
                          ELEVATION = 451.27 ft.
                          Right abutment = station 0
                          RP       = station 57
                          RE pier  = station 318
                          LE pier  = station 328
                          Left abutment = station 649
DSSB: RM = Bolt set vertically in right abutment at station -2.  
            ELEVATION = 446.32 ft.
      RP = Wire-weight gage at station 54. 
            ELEVATION = 449.49 ft.
APPR: RP = Bolt set in tree about 650 ft upstream, right bank.  
            ELEVATION = 448.09 ft.
EXIT: RP = Bolt set in pole about 650 ft downstream, right bank.  
            ELEVATION = 439.22 ft.


SiteName:
Great Miami River at S.R. 128 at Hamilton, OH

Description:
The site is located at the Columbia Road Bridge (S.R. 128) crossing the
Great Miami River at Hamilton, Butler County, Ohio.  The Ohio Department
of Transportation (ODOT) bridge identification is "BUT-128-0855", but the
bridge is maintained by the Butler County Engineers Office (phone 513-867-
5744).  A USGS streamflow gage, Great Miami River at Hamilton (03274000),
is just downstream from the bridge on the right bank. Gage data are
available from 1927 (some fragmentary data are available to 1907).  The
bridge is located in a straight channel.
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
RM1 - chiseled square in left upstream sloping abutment apron (2nd. set of
panels from upstream side) painted orange under bridge near bike path.
Assumed elevation of RM1 =  96.52 ft.
MSL elevation of RM1 = 572.80 ft.


SiteName:
Hocking River at S.R. 278 at Nelsonville, OH

Description:
The site is located on the Ohio State Route 278 bridge crossing the Hocking
River, in Nelsonville, Athens County, Ohio.  A railroad bridge is located
approximately 200 ft upstream from the S.R. 278 bridge.  Flood flows are
contracted by the railroad bridge and generally remain contracted through
the S.R. 278 bridge.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
BM = USGS BM Nelsonville on State Highway 278 at bridge over the Hocking R.
21 ft. NW of, and level with centerline of hwy., in NW end of NE abutment
of bridge, standard tablet stamped "113 JVC 1959 685"
Elevation = 685.439 ft.
Assumed elevation = 100.00 ft.  used as datum for scour elevation data
presented (datum conversion to MSL = 585.439 ft).


Description:
The site is located at the State Route 67 bridge crossing Honey Creek in
Melmore, Ohio.  A USGS streamflow gage, Honey Creek at Melmore (04197100),
is just downstream from the bridge on the right bank.  Annual maximum
discharges (1961-1975) and daily discharge from 1976 to current year (1994)
are available.  The bridge is in a straight portion of a meandering channel.
The bridge section is a "panhandle section" with the main-channel flow
concentrated on the right side of the channel.  Pier 2 lies in the main
channel, and Pier 1 lies in the overbank. The channel was modified upstream
and downstream from the bridge during construction.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
RM1 = head of 3/8 in. brass bolt in top of right upstream bridge abutment,
Assumed elevation = 129.39 ft.
MSL elevation = 846.04 ft.


SiteName:
Little Miami River at S.R.350 at Fort Ancient,OH

Description:
The site is located at the State Route 350 bridge crossing the Little Miami
River at Fort Ancient, Warren County, Ohio. The drainage area for the site
is 675 sq. mi., and drainage from approximately 35 percent of this basin
is regulated by Caesar Creek Lake reservior.  The site is in a straight
reach of the Little Miami River.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
RM2 - chiseled square in left upstream concrete abutment.
Assumed elevation = 111.29 ft
MSL elevation = 679.12


SiteName:
Ottawa River at Township Road 122 at Lima, OH

Description:
The site is located at the Adgate Road (Shawnee Township Rd. 122) bridge
crossing the Ottawa River, west of the intersection with Collett Street
in Lima, Ohio.  The site is approximately 1000 ft downstream from the USGS
streamflow gage Ottawa River at Lima, Ohio (04187100). Gage data are
available from June 1988 to the current year (1994).  The Adgate Rd. bridge
is maintained by the Allen County Engineers Office (phone 419-228-3196).
The bridge identification is SHA-122-0.71. The bridge is in a straight
portion of a meandering channel.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurements.

DescElevREf:
BM (COE OR-2 831.637-1965) S.W. of Lima, Allen County, on the S.E. corner
of Standard Oil outfall near Adgate Rd. bridge over the Ottawa River,
near the S. 1/4 post of Sec. 2, T4S, N6E, Shawnee Twp.
BM established by Corps. of Eng. 1965, Floodplain Info. Report, Ottawa R. 1967
Standard disk stamped OR-2.
MSL elevation    =   831.637 ft


SiteName:
Scioto River at S.R. 4 near Prospect, OH

Description:
This site was approximately 2 miles north of Prospect, Ohio at the State
Route 4 bridge crossing the Scioto River, near the junction of Routes 4
and 203. The bridge was replaced in 1991 with a new structure with T-type
(hammerhead) piers.  Therefore, scour measurement was discontinued at
this site.  Bed-material samples were collected during annual low-flow
surveys. 
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
RM1 - chiseled square on top of left upstream abutment (Destroyed in 1991)
MSL elevation     = 915.27 ft.
RM3 - Lag bolt 2 ft above ground in power pole on left upstream bank 60 ft
upstream from the bridge.
MSL elevation     = 903.19 ft.


Description:
The site is located at the Ohio Route 22 bridge crossing Todd Fork in
Morrow, Warren County, Ohio. The Ohio Department of Transportation (ODOT)
identification for the bridge is WAR-22-1054.  The site is upstream from
the confluence with the Little Miami River.  Based on the scour
measurements, there appears to be some backwater effect from the
confluence with the Little Miami River.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
RM1 - chiseled square on streamward, upstream side of the right abutment.
MSL elevation     = 648.09 ft.


SiteName:
Killbuck Creek at C.R. 621 at Killbuck, OH

Description:
The site is at the Front St. (Holmes County Road 621) bridge crossing
Killbuck Creek in Killbuck, Holmes County, Ohio.  A USGS streamflow-gaging
station, Killbuck Creek at Killbuck (03139000), is 0.9 mi downstream from
the site at U.S. 62. Gage data is available from 1930 to current year (1994).
The site is in a straight reach with a wide, wooded floodplain along the
right bank.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
        when viewing the upstream face of the bridge while facing in the
        downstream direction.
        Slope in Vicinity (reported in Stream Site Data) is estimated
        from USGS 7.5-minute quadrangle topographic maps.
        Water-surface slope (if reported in Pier Scour Data comments section)
        is the measured slope between water surfaces at the approach and
        bridge sections during the scour measurement.

DescElevREf:
RM1 - Chiseled square on left upstream abutment.
MSL elevation     = 812.32 ft.


SiteName:
Pamunkey River at S.R. 614 near Hanover, VA

Description:
The site is located 2.0 mi east of Hanover, Virginia at the State Highway
614 bridge crossing the Pamunkey River.  The bridge, 282 ft long, has three
3-ft-wide piers constructed on pile footings spaced 81 ft apart.  The
left end of the bridge is approximately 3 ft lower than the right end.  The
piers are aligned with the flow at most stages.  There is a sand-bed channel
at this location, and a sand bar is generally located on the left bank 50-200
ft upstream from the bridge.  At high flows, the sand bed may shift, and the
sand bar may flush through the bridge opening.  The center pier tends to
collect floating debris, and the largest local-scour values at this site were
observed at the center pier.  High flows generally last several days, and the
flow generally peaks 1-2 days after the most intense period of rainfall.  The
streamflow-gaging station, located 100 ft downstream from the bridge on the
right bank, has a loop rating curve.  Normally, a good measurement can be made
near the peak flow.  The stage generally falls 4-5 ft per day after the peak.
There is some regulation of flow by Lake Anna.

DescElevREf:
Wire-weight gage: 30.30 ft gage datum
BM on top right bank, downstream abutment


SiteName:
Nottoway River at S.R. 653 near Sebrell, VA

Description:
The site is located 2.5 mi southwest of Sebrell, Virgina and 5.5 mi
upstream from Assamoosick Swamp at the State Highway 653 bridge crossing
the Nottoway River.  The bridge is 250 ft long and has three 2.9-ft-wide by
32-ft-long piers on wooden-pile foundations spaced 62 ft apart.  The piers
are slightly skewed to high flows (moving left to right), which causes greater
scour on the right side of the pier than on the left side.  There is a sand
channel bed at the site, which has been scoured out around the pile cap of the
right pier.  One or two large logs have lodged against the piles on the right
pier and have limited the depth of the scour hole.  There is a buried log at
the face of the right pier that had an unknown effect on the scour.  The piles
remain submerged in water year-round.  Flow at high stages will be around the
bridge on the roadway.  The streambed profile at this site is probably
controlled more by the bed shear in a channel bend rather than by local-scour
forces.  There is light two-way traffic on the bridge, primarily farming and
logging vehicles.

DescElevREf:
The streamflow gage datum is 5.94 ft.  A wire weight is located on the
downstream side of the bridge, with gage datum at elevation 25.552 ft.


Description:
This site is located at the U.S. Highway 460 westbound two-lane bridge
crossing the Bush River, about 3 miles west of Rice, Virginia. There are
two bridges at this site.  The eastbound bridge (also two lanes but older
and narrower than the westbound bridge) is located 150 ft upstream
(approximately the width of the westbound bridge opening).  No measurements
were made at the eastbound bridge because of the narrow width and traffic
load. The westbound bridge is 187.5 ft long and is supported by four concrete
piers on pile caps and steel piles. The 2.5-ft-wide, 43-ft-long piers are
continuous webs and are spaced 37.5 ft apart. The roadway is elevated and
there are no side channels, therefore all flow is under the bridge.  The
normal stream width is about 40 ft, but can spread to the full bridge
width during high flows.  The drainage area at this site is 64 square miles.
Bush River joins Briery River 0.2 miles downstream.  Briery River appears to
cause some backwater and reduced velocities at the bridge site.  The bed
material at the bridge site, probably fill material, has more sand and clay
than the bed material upstream from the bridge.  This site was discontinued
because of the small drainage area and backwater conditions.

DescElevREf:
USCGS Benchmark stamped F443 1965 is located about 2.8 miles east along
U.S. highway 460 from the post office in Farmville, Virginia to the mark
set in the top of the northeast wingwall of the eastbound bridge over the
Bush River, 18.0 ft northeast of the centerline of the highway and about
level with the highway.  The elevation is 301.768 ft MSL.
RM1--A chiseled notch painted blue on the upstream handrail near the
centerline of the main channel 89 ft west of the east end of the westbound
bridge is at elevation 307.28 ft MSL.
RM2--A chiseled notch painted blue on the downstream handrail near
the centerline of the main channel, 87 ft west of east end of the west-
bound bridge is at elevation 307.22 ft MSL.
RM3-- An HP nail in the powerline pole at the left downstream end of the
westbound bridge, 35 ft from downsteam edge of road and 2 ft above ground,
is at elevation 293.66 ft MSL.


SiteName:
Dan River at U.S. 501 at South Boston, VA

Description:
This site is located at the U.S. 501 bridge crossing the Dan River at
South Boston, Virginia.  The 360-ft-long, four-lane bridge has two
concrete piers spaced 121 ft apart.  Each pier, 3.17 ft wide and 83 ft
long, is a continuous web its entire length and is supported by pile
footings.  The bridge is very wide and includes wide walkways on both
sides and a wide median.  South Boston Police close the bridge when high
water inundates the approach road from the south.  Access to the
bridge during floods is from the north.  The bridge will probably not be
overtopped.  The water is normally too deep with too much suspended
sediment for the channel bottom to be visible.  Use of a fathometer and
sounding weights is required to determine if the footers are exposed
or if debris is located on the bottom.  This site was eliminated from
the scour-measurement program because of excessive floating and submerged
debris.

DescElevREf:
RM1 (gage)--Elevation 331.19 ft MSL, USGS tablet stamped 331 located in the
            northeast corner of north abutment pier of Norfolk and Western 
            Railway bridge.
RM1 (bridge)--Elevation 338.94 ft MSL, Chiseled square on downstream bridge
              at station 160.
RM2 (bridge)--Elevation 335.04 ft MSL, Chiseled sq on top of downstream right
              abutment.
RP1--Elevation 339.42 ft MSL, Chiseled notch with arrow on upstream side of
     bridge at station 169 (169 feet from left bank).
RP2--Elevation 338.88 ft MSL, Chiseled notch with arrow on downstream side of
     bridge at station 160 (160 feet from left bank).


SiteName:
Tye River at S.R. 56 near Lovingston, VA

Description:
This site is located at the State Route 56 bridge crossing the Tye River
6.8 miles southwest of Lovingston, Virginia, 4.8 miles upstream from
the confluence with the Piney River, and 3.5 miles downstream from Hat
Creek.  The bridge is 199 ft long and has three piers spaced 55 ft apart.
The piers, 2 ft wide and 41 ft long, are a continuous web of uniform width
supported by a footer keyed into undisturbed material.  The bridge is part
of a superelevated curve in the roadway, and the upstream side of the bridge
is lower than the downstream side.  The bridge is high above the streambed
and will probably not be overtopped.  The bridge has flow-through abutments
supported by piles.  Plans for the previous bridge (before 1985) are not
available.

DescElevREf:
Datum of gage is 578.39 ft.
RM5--Elevation 26.465 ft gage datum.  Chisiled square on downstream hand
     rail.  Probably on right bank.
RM6--Elevation 24.519 ft gage datum.  Chisiled square on upstream hand
     rail.  Probably on right bank.
MP1--Elevaton 26.656 ft gage datum.  Chisiled arrow at station 62 (62 ft
     from right bank) .
MP2--Elevation 24.735 ft gage datum.  Chisiled arrow at station 62 (62 ft
     from right bank).


SiteName:
Little Nottoway River S.R. 603 nr Blackstone, VA

Description:
This site is located in the headwaters of the Nottoway River, just north of
the intersection of State Highways 602 and 603, and 2.5 miles west of
Blackstone, Virginia.  The bridge, 210 ft long and 24 ft wide, is supported
by three concrete piers on pile foundations.  The tapered piers are spaced 52
ft apart. The piers are numbered from right to left.

DescElevREf:
RM1--Elevation 272.70 ft MSL.  Chiseled square painted blue in left upstream
     end of headwall of culvert on Route 603, 30 ft south of junction of
     Route 603 and Route 602.
RM2--Elevation 279.39 ft MSL.  Chiseled notch painted blue on upstream
     handrail post at centerline of main channel, 57 ft north of south end
     of bridge and 263 ft south of north end of bridge.  Marked with a
     chiseled arrow.
RM3--Elevation 279.36 ft MSL.  Chiseled notch painted blue on downstream
     handrail post at centerline of main channel approximately 50 ft north
     of south end of bridge and 270 ft south of north end of bridge.  Marked
     with a chiseled arrow.
  BM--Elevation 451.239 ft MSL.  On line 104 located 3.0 miles northwest of
      Blackstone, Va.  C&GS reference mark disk at the NEBO station site: 65.28
      ft south of the station, 55.2 ft east of the north corner of a frame
      house and just east of a wire fence line, set in the top of a concrete
      post, flush.  Stamped NEBO NO 1 1965.


SiteName:
Reed Creek at S.R. 649 near Wytheville, VA

Description:
This site is located at the State Route 649 bridge crossing Reed Creek,
2.5 miles east of Wytheville, Virginia and 0.2 miles north of State Route
11.  The bridge, 180 ft long, has two concrete piers spaced 70 ft apart.
The piers, 2 ft wide and 30 ft long, are supported by footers on
bedrock.  A layer of alluvium several ft thick is present.  A gravel
storage area is located on the right bank 200 ft upstream from the
bridge.  This is apparently the source of much of the gravel in the
streambed at this site.  Elevations from a field survey of the site
do not correspond to elevations from the bridge plans (obtained after
the survey).  Elevations reported here are from the field survey.  Bridge
dimensions are from the construction plans.

DescElevREf:
RM1--Elevation 100.00 ft gage datum.  Chiseled + on left upstream concrete
     guard rail of bridge (Northwest corner of bridge).
RM2--Elevation 99.68 ft gage datum.  Chiseled + on left downstream concrete
     guard rail of bridge (Northeast corner of bridge).
RP1--Elevation 98.26 ft gage datum.  Chiseled notch on top of upstream
     concrete guard rail 100 ft from left abutment.
RP2--Elevation 98.20 ft gage datum.  Chiseled notch on top of downstream
     concrete guard rail 109 ft from left abutment.


SiteName:
North Fork Holston River at S.R. 633 near North Holston, VA

Description:
This site is located at the S.R. 663 bridge crossing the North Fork
Holston River, 1 mile southeast of North Holston, Virginia and 2 miles
southwest of Broadford, Virginia.  The bridge, 208 ft long and 29 ft wide,
has three concrete piers spaced approximately 50 ft apart.  The three piers,
2 ft wide and 29.5 ft long, are continuous webs supported by footers on
bedrock.  The abutments are supported by piles and are protected by flow-
through riprap aprons.

DescElevREf:
RM1--Elevation 1748.42 ft msl.  Chiseled square on northwest abutment of
     bridge, top at northwest corner.
MP1--elevation 1752.06 ft MSL.  Chiseled V on upstream concrete rail 74 ft
     from south end (left bank) of bridge.
MP2--Elevation 1751.98 ft msl.  Chiseled V on downsream concrete rail 74
     ft from south end (left bank) of bridge.
MSL elevations were computed from elevation of top of piers from bridge plans
and field survey.


SiteName:
Mississippi River at S.R. 51/150 at Chester, Ill.

Description:
Detailed bridge-scour measurements were made at the State Route 51/150 crossing of the Mississippi River at Chester, Illinois; at river mile 109.9 above the Ohio River and about 70 river miles south of St. Louis Missouri.  This highway is numbered as Missouri State Route 51, and Illinois Sate Route 150.  The USGS has operated a discharge gaging station (USGS Station No. 07020500) at this site since 1942 and river stage records have been recorded at this site since 1891.  The datum of the gage is 341.05 feet above NGVD 1929 datum (MSL).  Periodic bed-material samples and daily suspended-sediment samples were obtained at the gage during the flood.

The Mississippi River drainage area at this stie is 708,600 sq. mi.  The Mississippi River flows at the eastern (Illinois) edge of its flood plain in the study reach.  The Illinois bank rises steeply at slopes of 0.1 to 0.7 ft/ft from the main channel to about 280 ft above normal river levels.  The main channel is fairly straight in the study reach.  There is a gradual bend to the left about 2.5 miles upstream, a very gradual bed to the right at the bridge, and a gradual bend left about 2 miles downstream.  The main channel is about 1700 feet wide at the bridge and averages about 2200 feet wide over a 4-mile reach centered at the bridge.  The annual average daily discharge at this site is 198,700 cfs.

DescElevREf:
All elevations are presented in ft reference to MSL.

The gage datum at Chester is 341.05 ft MSL and all reference to stages refer to this datum.

Horizontal positioning of the data were accomplished with a range-azimuth tracking system.  The coordinates are a local grid in feet.


SiteName:
Mississippi River at S.R. 3 at St. Paul, MN

Description:
At east side of downtown St. Paul, MN. Undivided 4 lane freeway bridge 3,363
ft long of 29 spans with span 9, (270ft), span 10 (362 ft),and span 11 (250.5
ft) over river channel.  Spans are numbered from south end.  End spans carry
highway 3 over streets in flood plain now protected by levees which confine
flow through St. Paul to 1200ft width or less where floods previously had
relief above 700 ft across 3500ft of flood plain on right bank.  Piers in
channel initially had riprap for 20 ft out all around the bases. Named
"Lafayette Freeway Bridge."
Note: Piers 8 - 11 have wide beveled corners

DescElevREf:
Benchmarks:
#6244A, in SE corner, 0.8 ft north of south end of east concrete railing.
  Elev. 730.569 ft.
#K349, set vertically in south face of southeast most concrete pier, 17.4 ft
  east of east rail of RR tracks, Elev. 763.933 ft.
#L254, in bridge pier 1.8 ft west of southeast corner of east pier in second
  row of piers from south end of bridge.  Elev. 704.769 ft.
#W250, 34 ft north of Warner Road in east face of first pier east of river,
  2.5 ft south of northeast corner or pier. Elev. 708.201 ft.
Additional marks available from MN DOT mapping unit, tel (612)296-3027.


SiteName:
Clear Creek at U.S. 33 near Rockbridge, OH

Description:
The site is located at the US Route 33 bridge crossing Clear Creek north of
Rockbridge, Hocking County, Ohio. The Ohio Department of Transportation (ODOT)
bridge identification is "HOC-33-0060". Site is located 200 feet upstream of
the confluence with the Hocking River and is subject to backwater from the
Hockng RIver. Site is located near USGS streamgage Clear Creek nr Rockbridge
(03157000) and is located approximately 10000 feet upstream of the bridge
(data available from 1939 to current year). Care had to be taken to obtain
high-flow scour measurements not affected by backwater from the Hocking River.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       7.5-minute quadrangle topographical maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 - Chiseled square on streamward side of left upstream abutment
(the northeast abutment).
MSL elevation = 765.83 ft


SiteName:
Grand River at S.R. 84 near Painesville, OH

Description:
This site is located at the SR 84 bridge crossing the Grand River near
Painesville, Lake County, Ohio. The Ohio Department of Transportation (ODOT)
bridge identification is "LAK-084-1888". (Upstream of Big Gordon Creek)
USGS streamgage Grand River at Painesville (04212100) is located on left
downstream abutment of bridge. Data available from 1974 to current year.
Site is located on large bend in channel, and flow velocity is greatest
at left side of channel. Also, there is an large wooded island located
upstream of bridge and  at highflow, the flow splits around the island.
The right portion of the flow attacks the right most pier at 90 degrees
(or directly at the long axis of the pier) causing a large scour hole
along the side of the pier.
Bed-material samples were collected during an annual low-flow survey.
Note: All piers are referenced numerically, increasing from left to right,
      when viewing the upstream face of the bridge while facing in the
      downstream direction.
      Slope in Vicinity (reported in Stream Site Data) is estimated
      from USGS 7.5-minute quadrangle topographic maps.
      Water surface slope (if reported in Pier Scour Data Comments section)
      is the measured slope between water surfaces at the approach and
      bridge sections during the scour measurement.

DescElevREf:
RM2 - Chiseled square on top of left upstream abutment.
MSL elevation = 620.35


SiteName:
Great Miami River at S.R. 41 at Troy, OH

Description:
This site is located at the SR 41 bridge crossing the Great Miami River at
Troy, Miami County, Ohio. THe Ohio Department of Transportation (ODOT) bridge
identification is "MIA-41-0833".
Site is located roughly 4500 feet downstream of USGS streamgage Great Maimi
River at Troy (03262700). Streamgage data available from 1962 to current year.
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left ot right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 - Chiseled square on right upstream abutment (northwest corner of bridge)
MSL elevation = 830.34 ft


Description:
This site is located at the US 36 bridge crossing the Mad River at Urbana,
Champaign County, Ohio. USGS streamgage Mad River nr Urbana (03267000) is
located on the left downstream abutment. Streamgage data available from 1939
to current year. Some data available 1925-1931. THe Ohio Department of
Transportation (ODOT) bridge identification is "CHP-36-1244".
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM7 - Aluminum tablet in top of right upstream wingwall (northwest corner of
of bridge). Tablet stamped (US Dept. of Interior, reset 1969).
MSL elevation = 1002.46


Description:
This site is located at the SR 68 bridge crossing Massies Creek at Greene
County, Ohio. Site is located downstream of USGS streamgage Massies Creek at
Wilberforce (03241500, Drainage area = 63.2 sq. mi. at gage). ODOT ID of US68
bridge is GRE-68-1340. Scour site is located roughly 500 ft. downstream of the
confluence of Massies Creek and Oldtown Creek.
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge, while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 = Chiseled square on landward side of south upstream abutment.
MSL elevation = 827.16 ft


SiteName:
Maumee River at U.S. 127 near Sherwood, OH

Description:
This site is located at the US 127 bridge near Sherwood, Defiance County,
Ohio. The site is located approximately 800 feet upstream of Penn Central rail
line THe Ohio Department of Transportation (ODOT) bridge identification is
"DEF-127-0053".
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
BM1 - ODOT brass tablet on downstream left wingwall.
MSL elevation = 703.17


SiteName:
Salt Creek at U.S. 50 near Londonderry, OH

Description:
This site is located at the US 50 bridge crossing Salt Creek near Londonderry,
Ross County, Ohio. Site is located approximely two-thirds of a mile from the
Ross - Vinton County line. The Ohio Department of Transportation (ODOT) bridge
identification is "ROS-50-3692".
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM2 - Bolt in power pole on left upstream bank. Approximately 15 feet upstream
      of bridge.
MSL elevation = 601.02 ft.


SiteName:
Scioto River at S.R. 159 at Chillicothe, OH

Description:
This site is located at SR 159 crossing the Scioto River at Chillicothe,
Ross Couty, Ohio.  The site is located about 0.25 mile North of were the B&O
Railroad crosses S.R. 159. USGS streamgage Scioto River at Chillicothe
(03231500) located 1400 feet downstream of scour site bridge. Gage data
from 1920 (some fragmentary data available to 1907). Bridge is located at
downstream end of large bend of the channel.
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing form left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 - USGS Reference mark (brass tablet) located on top of upstream right
abutment (southwest corner of bridge).
MSL elevation = 630.82


SiteName:
Sugar Creek at U.S. 250 at Strasburg, OH

Description:
This site is located at the US 250 bridge crossing Sugar Creek at Strasburg,
Tuscarawas County, Ohio. Site is located at USGS streamgage Sugar Creek
at Strasburg  (03124500), data available from 1961 to current year. Also,
streamgage data available from 1931-1933 and 1935-1939. Note : of the 300 sq.
miles of drainage area for this site, 96% is regulated by Beach City Dam.
The Ohio Department of Transportation (ODOT) bridge identification is
"TUS-250-0511".
Bed-material samples were collected during an annual low flow-survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM5 - Chiseled cross on anchor bolt for guard rail at base of ground, 50 feet
downstream of USGS streamgage shelter located on left (east) bank.
MSL elevation = 912.66 ft


SiteName:
Tuscarawas River at Walnut Rd at Massillon, OH

Description:
This site is located at Walnut Rd bridge over the Tuscarawas R. in Massillon,
Stark County, Ohio. Bridge is maintained by Stark County Engineers Ofice.
USGS streamgage Tucarawas River at Massillon (03117000) is located
approximately 1 mile downstream of scour site. Steamgage data available from
1937 to current year, (prior to April 1938 monthly discharge only).
No highflow scour measurements were obtained at this site and the bridge was
renovated (new deck and riprap placed around piers) during 1992 rendering the
site unusable for scour measurement.
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 = Chiseled square on the left upstream wingwall (northeast wingwall).
MSL elevation = 944.76


SiteName:
Tuscarawas River at C.R. 14 near Port Washington, OH

Description:
This site is at CR 14 over the Tuscarawas R. at Port Washington, Tuscarawas
Cty, Ohio. It is located apporximately 9.6 miles upstream of USGS streamgage
Tuscarawas River at Newcomerstown (03129000): with streamgage data
available from 1921. Flow is regulated by eight flood-control reservoirs
at points upstream 40 to 64 miles from the Newcomerstown streamgage.
The bridge is maintained by the Tuscarawas County Engineers Office.
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
BM1 - Corps of Engineers brass tablet on the left downstream abutment,
(southeast corner of the bridge). Tablet is marked with the elevation 820.63
feet.
MSL elevation = 819.86 ft


SiteName:
Wakatomika Creek at S.R. 16 near Frazeysburg, OH

Description:
This site is located at the SR 16 bridge crossing Wakatomika Creek, .3 mi W of
Frazeysburg, Ohio. Site is approximatley 2.5 mi. east of the intersection of
State Routes 16 and 586. Site is located approximately one mile downstream
of USGS streamgage Wakatomika Creek near Frazeysburg (03144000): streamgage
data available from 1936 to current year. The Ohio Department of
Transportation bridge identification is "MUS-16-0350".
Bed-material samples were collected during an annual low-flow survey.
Notes: All piers are referenced numerically, from the left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 = Chiseled square located on top of east upstream abutment.
MSL elevation = 758.21 ft


SiteName:
Walnut Creek at C.R. 17 near Ashville, OH

Description:
This site is located on CR 17 (Walnut Cr. Pike Rd) over Walnut Cr., Ashville,
Pickaway County, Ohio.  Bridge is maintained by Pickaway County Engineers
Office. Bridge is located within a relatively straight reach of Walnut Creek.
Bed-material samples were collected during annual low-flow surveys.
Notes: All piers are referenced numerically, increasing from left to right,
       when viewing the upstream face of the bridge while facing in the
       downstream direction.
       Slope in Vicinity (reported in Stream Site Data) is estimated
       from USGS 7.5-minute quadrangle topographic maps.
       Water-surface slope (if reported in Pier Scour Data comments section)
       is the measured slope between water surfaces at the approach and
       bridge sections during the scour measurement.

DescElevREf:
RM1 - Chiseled square on streamward side of left upstream wingwall.
MSL elevation = 714.83 ft


SiteName:
Minnesota River at CR 14 near Lac qui Parle, MN

Description:
CR 14 over Minnesota River is located in a rural area.  Satellite images show four oxbow lakes in the vicinity of the bridge, however, the current channel is relatively straight having a sinuosity of 1.07.  The flood plane to the left is wide as indicated by the oxbow lakes.  The highway on the left floodplain is overtopped at the 25-year flood (17,500 cfs).  The approach from the right is much steeper with a much narrower flood plain.  The floodplains are primarily forest and with some pasture. 

In 1994 a relief bridge in the left approach was apparently removed and the main channel bridge widened.

DescElevREf:
All elevations and stages are referenced to mean sea level, based on the elevation of the finished bridge deck, take from the plans dated 5-4-1990.


SiteName:
Pomme De Terre River at CR 22 near Fairfield, MN

Description:
Swift county road 22 over the Pomme De Terre River is three-span structure supported by round concrete pile bents.  The site is located in a rural / agricultural area.  During the flooding in April 1997, the USGS visited this site four times.  The cross sections show a progression of scour at the right abutment. During all three visits the floodplain flow was concentrated in the right floodplain.  This concentration of flow in the right floodplain is likely due to the channel alignment upstream of the bridge.  The field crew searched for but could not define a location of flow reattachment along the right embankment.  Flow was towards the main channel along the entire length of the embankment.  The flow separated from the right embankment, nearly perpendicular to the main channel flow, and joined the main flow just left of the rightmost pier. During the 4-5-97 visit the flow from the right floodplain was so strong that a standing wave formed upstream of the bridge where the floodplain and main channel flow began mixing.  The area from the rightmost pier to the right abutment was primarily slack and reverse flow.  A slump failure in the right upstream highway embankment was observed during the last visit on 4-9-97.  In July 1997 it was observed that riprap was used to fill scour at the right wingwall.

Cross-section data were collected using a chart-recording echo sounder with the transducer mounted on a knee board.  The charts were digitized and scaled.  Velocities were measured using standard discharge measurement procedures and a Price AA cup meter.

Manning's n reported the stream data are for the upstream reach.  A complete distribution of Manning's is provide below:

Upstream  Left    Main   Right    Downstream   Left    Main    Right
High       0.12   0.035   0.13                  0.09   0.035   0.09
Typical    0.10   0.030   0.12                  0.08   0.030   0.08 
Low        0.08           0.08                  0.07           0.07

DescElevREf:
Water-surface elevations were measured from the bridge deck.  The elevation of the bridge deck was determined from the bride plans.  All measurements were made between the leftmost pier and the left abutment.  

Date         Time           Upstream        Downstream
4-4-97                       1040.13             1039.85
4-5-97      1430             1040.57             1040.27
4-9-97      1800             1041.2
7-15-97     1410             1032.75

A local right-hand coordinate system was established with the postive y-axis in the upstream direction and the x-axis parallel to the upstream face of the bridge.  This resulted in x-coordinates increasing from right to left.  Since step backwater models typically us left to right coordinates, stationing was added which increases from left to right.  The stationing on the two sections 500-ft upstream was adjusted so that the main channel aligned with the main channel at the bridge.


SiteName:
Brazos River at FM2004 near Lake Jackson, TX

Description:
FM 2004 crosses the Brazos River west of Lake Jackson, Tex. (figure 1).  This site is about 25 river-kilometers from the Gulf of Mexico.  The FM 2004 bridge over the Brazos River has 11 spans supported by pile bents (figure 2).  The bents are composed of batter piles with a 1.2-m thick footing located at elevation 0.61 m MSL (bottom of cap), which is just above the normal water surface.  Three columns extend from the footing to a bent cap, which supports the bridge deck.  A web wall extends from the footing up about 4 m between the three columns.  The batter piles are exposed to drifting woody debris during normal flow conditions.  Dive reports (Texas Department of Transportation, 1994) and several visits to the site by USGS personnel prior to the October 1994 flood noted the presence of debris on bents 6, 7, and 8.  The accumulations on bents 7 and 8 were submerged and much smaller than the one on bent 6.  During data collection in October 1994, the accumulation of woody debris centered on bent 6 was approximately 75 ft wide, and extended about 45 ft upstream from the nose of bent 6.  The accumulations at bents 7 and 8 were submerged and could not be visually inspected.

The Brazos River has long reaches of nearly straight alignment upstream from Brazoria, Tex. (located about 15 km upstream from FM 2004) and downstream from FM 2004; however, between Brazoria and FM 2004, the Brazos River is highly sinuous with several bends of nearly 180? (figure 1). The nearest USGS gaging station is located approximately 34 river-miles upstream near Rosharon, Tex.  The discharge at Rosharon reached a record peak of 84,400 cfs on October 22, 1994. The October 1994 flood attenuated between Rosharon and FM 2004 with a measured discharge of 69,300 cfs at FM 2004 on October 23, 1994.  The water-surface elevation at FM 2004 was nearly constant, oscillating about 0.3 ft from October 22-24, 1994.

Water-surface elevations along both banks were surveyed from about 2,000 ft upstream from the bridge to about 1,000 ft downstream from the bridge using a 5-second total station. Upstream from the bridge, the water-surface elevation on the left bank (outside of upstream bend) was about 0.6 cm higher than the water-surface on the right bank (inside of upstream bend). This differential caused a significant difference in the water-surface slopes measured along each bank.  The water-surface slope along the left bank was about 0.00046 ft/ft while it was only 0.00004 ft/ft along the right bank. Downstream from the bridge, the water-surface elevations were fairly uniform on both banks with a slope of 0.00025 ft/ft. The drop in water-surface elevation from the upstream edge of the debris accumulation to the downstream edge of bent 6 was 0.6 cm.  Overall, the water-surface elevations and slopes are consistent with the velocity distributions measured by the BB-ADCP.

The nearest hydrograph is at Rosharon, Texas:

08116650 BRAZOS RIVER NEAR ROSHARON, TX
LOCATION 
Lat 29°20'58", long 95°34'56", Fort Bend-Brazoria County line, Hydrologic Unit 
12070104, on right bank at downstream side of bridge on Farm Road 1462, 2.0 mi 
downstream from Big Creek, 2.1 mi upstream from Cow Creek, and 7.3 mi west of 
Rosharon and at mile 56.7. (MAP) 
DRAINAGE AREA 
45,339 mi², approximately, of which 9,566 mi² probably is noncontributing. 
PERIOD OF RECORD 
April 1967 to September 1980, Apr. 25, 1984, to current year. (Details) 
GAGE 
Water-stage recorder. Datum of gage is sea level. 
REMARKS FOR 1997 WATER YEAR DATA 
Records good except those for estimated daily discharges, which are fair. Since 
installation of gage in April 1967, at least 10 percent of contributing drainage area has been regulated by six upstream reservoirs with a combined capacity of 
4,828,600 acre- ft, of which 3,482,690 acre-ft is for flood control. Flow is affected at times by discharge from the flood-detention pools of 145 floodwater-retarding structures with a combined detention capacity of 152,800 acre-ft. These structures control runoff from 450 mi². Water is diverted above station for irrigation, industrial, and municipal supply and materially affect low flows. Satellite telemeter at station. 
EXTREMES OUTSIDE PERIOD OF RECORD 
Maximum elevation since at least 1884, 56.4 ft about Dec. 11, 1913, from information by the Texas Department of Transportation.

DescElevREf:
Vertical elevations are referenced to MSL.  The local reference point was a bolt in the concrete base of a power pole and had an elevation of 16.75 ft MSL per TxDOT.  The water surface elevation under the bridge was measured from the top of the web wall at pile bent 6.  The elevation of the top of the web wall and all other water-surface elevations were surveyed with a total station.

A local coordinate system was established for horizontal coordinate.  The origin of the local coordinate system is near the right abutment.  The y-coordinate increase from right to left at the bridge and is aligned with the upstream face of the bridge.  The x-coordinate increases in the downstream direction.


SiteName:
Mississippi River at I-255 (Jefferson Barracks Bridge) near St. Louis, MO

Description:
The I-255 (Jefferson Barracks Bridge) over the Mississippi River is located just south of St. Louis, Missouri.  The river in this reach varies from 2,000 to 2,500 ft wide.  The thalweg crosses from the left (Illinois) bank to the right (Missouri) bank upstream from the bridge and follows the right bank through the bridge and crosses back to the left bank downstream from the bridge.  The channel alignment is a very gentle bend with a high bluff along the right upstream bank.  The left floodplain is about a mile wide and is predominately farmland.  A levee restricts the extent of the left floodplain.  The bridge is 4,003 ft long and is supported by 14 piers.  Piers are numbered from right to left (Missouri to Illinois). The navigation channel is along the right (Missouri) bank.  Piers 12 and 13 support the navigation span of 910 ft.  Piers 8 through 10 are set on a large sand bar along the left (Illinois) bank, which is exposed during very low flow.  Dikes have been installed by the U.S. Army Corps of Engineers along the left bank both upstream and downstream of the bridge to maintain a sufficient depth in the navigation channel during low flow.

DescElevREf:
The water-surface elevations were measured at a staff gage about 1,000 ft downstream from the bridge.  The staff gage had a datum of 377.7 ft MSL.  All elevations are presented in ft MSL.

Horizontal positioning of the velocity profiles and bathymetry was measured using a range-azimuth positioning system.  The horizontal coordinates are in an arbitrary local grid.  The bridge was correctly positioned in the grid by surveying 2 or more piers from each instrument setup location.  All horizontal coordinates are in ft.


SiteName:
Mississippi River at Martin Luther King Memorial Bridge (S.R. 799)  at St. Louis, MO

Description:
Martin Luther King Memorial Bridge is located in downtown St. Louis, Missouri. St. Louis occupies the right descending bank and there is industry along the left descending bank.  The floodplain is constricted on both sides by levees.

DescElevREf:
Vertical elevations are referenced to MSL.  The surveyed streambed elevations were referenced to the stage reported at the St. Louis gage, which is about 3/4 mile from the study site.

Horizontal control is approximate, no tracking or GPS was used.  A paper chart was used to record the data and the location of structural members marked on the chart.  The chart was then digitized and scaled.


SiteName:
Middle Fork Crow River at S.R. 4 near Manannah, MN

Description:
S.R. 4 runs north and south through low relief terrain of pastures and meadows, with some areas of woody vegetation.  The nearest town of Manannah is located to the northwest.  According to the MnDOT bridge plan notes, “The channel appears to have been dredged and straightened.  No records at courthouse of it being a public ditch.”  The channel in 1997 still appear unusually straight, but banks were well vegetated and appeared stable.  There is no gaging station near this site, but according to the bridge plans, local residents reported a historic high water of 1124.9 ft MSL, which occurred in the spring of 1952.  The current bridge built in 1955 apparently replaced a smaller bridge (having an opening of only about 25 ft), which was located about 20 ft upstream.  The construction plans indicated that the contractor was to clean out the channel and dress slopes to the section shown in the plans, for a distance of 60 ft both sides of the highway centerline.  The design cross section had a bottom width of 26 ft at an elevation of 1115.25 ft MSL with side slopes of 2:1.

Data collected in 1997 was collected after the flood peak had passed.  The time of the peak is not known but based on highwater marks the peak appeared to be at 1122.1 ft MSL, approximately 1.86 ft higher than the stage of 1120.25 ft MSL measured of April 4, 1997.

DescElevREf:
All elevations and stages are referenced to mean sea level, based on the elevation of the finished bridge deck.


SiteName:
Pomme De Terre River at U.S. 12 near Holloway, MN

Description:
Bridge 5359 is located 10.7 miles west of Danvers, Minnesota on U.S. Route 12 over the Pomme De Terre River.  The single-span steel-truss structure was constructed in 1933 with a maximum span length of 88.3 ft.  The upstream floodplain consists of a mixture of open agricultural land with scattered trees and brush.  There is a park on the upstream left bank.  The area downstream is more heavily wooded and is classified on the maps as a wetland area.

The bridge has vertical-wall abutments with wing walls.  Each abutment and wing wall rest on concrete footings supported on timber piling.  Neither abutment is riprapped nor do they have any other scour protection measures.  A field investigation conducted by BRW, Inc. (during a scour evaluation) revealed no evidence of significant scour at the abutment face.

Regarding bed material, BRW reported the following: 

The stream bed material in the vicinity of the bridge generally consists of fine grained organic silty sand.  A sieve analysis of a field sample indicated a mean diameter of 0.00049 ft.  Based on the soil borings and blow counts documented for the bridge construction, the river bed materials appear to become harder and denser as depth increases. Since the type of the soil was not recorded, it is difficult to ascertain the makeup of the soils at depth.

BRW noted minimal debris during their field investigation and the USGS note no debris during the flood measurements.  There are trees locate on the upstream floodplain so the potential for debris exists, but is probably low.

The nearest gaging station is located at Appleton, MN approximately 15 miles downstream.  Station No. 05293960 has over 60 years of record.  There is one small drainage noted between the site and Appleton on the right floodplain.

Summary of flood frequencies from BRW’s scour analysis:

Return Period - Discharge (cfs)
  10 yr - 2,075
  50 yr - 3,925
100 yr - 4,880
390 yr - 7,130 overtopping flood
500 yr - 7,530

A scour-monitoring plan had been implemented by MNDOT and was available at the time of the flood.  This bridge was scheduled to be replaced and has now been replaced with a new structure.

The stream data portion of the database only allows one set of Manning's n values.  Below is the estimated upstream and downstream values.

Upstream  Left    Main   Right    Downstream   Left    Main    Right
High       0.08   0.035   0.08                  0.12   0.035   0.12
Typical           0.030                         0.08   0.030   0.08 
Low        0.05           0.05

DescElevREf:
Elevations are referenced to MSL based on values provided by MNDOT on their scour monitoring plan.  Plans for the new bridge developed by BRW showed elevations 30 ft higher.  The scour report from BRW agreed with the MNDOT scour monitoring plan and thus, that elevation reference was used.  The top of curb near the east abutment was used and was to have an elevation of 998.7 ft.  The horizontal stationing of data collected from the bridge deck was referenced to the left abutment then adjusted in post-processing to be consistent with stationing used in the BRW WSPRO model.  Distance of ADCP data from the bridge was visually estimated.  Horizontal stationing for the ADCP is based on bottom tracking.  The stationing was visually adjusted to agree with the BRW WSPRO model.

(3/8/2000) Note: The elevations that were provided by MNDOT, and the elevations from the BRW sour report, when used to build a HEC-RAS model of the bridge section, were discovered to be inconsistent with the downstream gaging station (Appleton) elevations during the 1997 flood.  MNDOT was again contacted and it was discovered that elevation 995 ft above MSL on the BRW scour report should actually be 1023.9 feet above MSL, thus validating the new bridge plan elevations.  Therefore, the elevation of the top of curb near the east abutment should actually be 1027.6 ft, making the bridge section more consistent with elevations upstream at CR 22 bridge (see entry 73) and downstream at the Appleton gaging station.  A correction of +28.9 ft should be made to MNDOT's reference elevation on their sour monitoring plan and all elevations from the BRW sour report.  The   April 1997 field data, found in the attached excel file (us12pdt-REV.xls), has already been corrected to reflect the new reference elevation.


SiteName:
Auglaize River at S.R. 198 near Wapakoneta

Description:
This site is located at the State Route 198 bridge crossing the Auglaize River North of Wapakoneta, Auglaize County, Ohio.  The Ohio Department of Transportation (ODOT) bridge identification is BUT-198-0971.  The site is located 2 miles upstream of Two Mile Creek.

Notes:  All piers are referenced numerically, increasing from left to right, when viewing the upstream face of the bridge while facing downstream.  Slope in Vicinity (reported in Stream Site Data) is estimated from USGS 7.5 minute quadrangle topographic maps.  Water-surface slope (if reported in Pier Scour Data comments section) is the measured slope between water surfaces at the approach and bridge section during the scour measurement.

DescElevREf:
RM1 - Chisled square on streamward side of right upstream wingwall.
MSL elevation = 830.96


SiteName:
Chariton River @ State Route 129 near Prairie Hill, MO

Description:
The study site is located on the Chariton River at mile 11.73 of State Route 129, about 9 miles north of the town of Salisbury (at the intersection of State Route 129 and U.S. Route 24), and about 18 mile south of the intersection of State Route 129 and U.S. Route 36.  The Chariton River basin above the bridge covers approximately 1,870 square miles, and is partially regulated by Rathbun Lake in Iowa (station 06903880) built in 1969.  The period of record for this station is from October 1928 to the current year, with an annual mean flow of 1,273 cfs, and an instantaneous peak flow of 33,600 cfs recorded on May 27, 1996 (stage 22.33 ft, gage datum).

The structure number for this site is L-344.  The Missouri Dept of Transportation (MoDOT) built the current bridge in 1949 and channelized the Chariton River, replacing a structure over the old channel on the current right floodplain.  The channel has been regularly dredged, evidenced by the dredge piles observed on both banks.

Structure L-344 consists of 60'-70'-70'-60' continuous I-beam spans supported by three dual-conical concrete column piers with partial web walls, and spill-through abutments. The piers and the abutments are founded on piling; the pier piling is driven to an elevation of 585-590 ft, and the abutment piling is driven to an elevation of 607 ft.  The right abutment extends into the channel, whereas the left abutment is set back about 35 feet from the top of the left bank.  Both the left bank and the right abutment are covered with large chunks of concrete debris and riprap.

Apparently due to channelization, this site is prone to catch drift. Several of the flood measurement on record indicate a large debris drift pileup on the central pier and the consequent scour that occurs as a result of the raft.  Several measurements of scour have occurred at this site, by Larry Becker and by Dave Mueller/Rick Huizinga et.al.  The propensity to catch debris and the resulting scour are what make this site an interesting case study.

A review of flood measurement notes seems to indicate that this site does not experience substantial scour of any form when there is no debris raft.  The bed elevations in these cases are consistently steady, matching the ground line at the time of construction of L-344 and a channel survey taken in November 1999 during low flow. The only change in the channel from the time of construction is a widening and lateral migration of the channel.  The channel configuration--with the dredge banks on either side and low road embankments on both floodplains--is such that for flows less than bank-full, flow direction is straight through the bridge opening with little contraction of flow, resulting in no contraction scour and minimal pier scour.  For greater than bank-full flows, flow direction (in the roadway ditches upstream and downstream of the bridge) is observed to be AWAY from the channel into the floodplains, again resulting in no contraction scour and minimal pier scour.  However, for floods where a debris raft forms on the central pier, the bed elevations drop by as much as 20 feet in what appears to be a combination of contraction scour (caused by the reduced flow area due to the raft) and local scour effects caused by the raft and pier.

DescElevREf:
Bridge data elevations are taken from MoDOT plans, but are consistent with gage datum.


SiteName:
Cedar River at US 218 near Janesville, IA

Description:
U.S. 218 over the Cedar River was relocated from the north edge of Janesville to a location further north in 1992. Maps from Delorme do not have the bridge in the correct (new) location. The highway now crosses the Cedar River near the apex of a river bend. This new location consists of two parallel bridges, each with two lanes of traffic and wide shoulders.  Each bridge has six round-nose piers. The piers of the downstream bridge are located directly downstream of the piers on the upstream bridge. The piers are hammer-head type piers that are 18 ft long at the water surface and hammer-heads are 40 ft long. There was a rock dike (berm) about  100 ft upstream extending from the left abutment out the top of bank. Although the concrete portion of the abutments is not continuous between the bridges, there is only a short distance and shallow ditch between the two bridges, so the abutments have been treated for hydraulic purposes as if they were continuous abutments. The right abutment has a guidebank on the upstream side to help redirect flow from the right floodplain. 

This site is used by the USGS for making streamflow measurements. The actual gage is located in a park about 0.25 miles downstream from the bridge.

The bridge is located near the apex of a bend in the river. Standing on the bridge looking upstream reveals a straight channel for about 500 ft and looking downstream, a straight channel for a much longer distance. The channel beyond 500 ft is divided by several islands. The description of the USGS gaging station states that the streambed is composed of sand, gravel, and rock.

The left floodplain is fairly narrow, high, and thinly wooded. The right floodplain is low with trees and a bushy undergrowth. A small field is located on the upstream right floodplain and a residence with large yard is located on the downstream right floodplain. In both situations the field and yard are several hundred feet from the streambank and the area between the streambank and the field or yard is covered by trees with a bushy undergrowth. The narrow left floodplain is almost completely spanned by the bridge, but there is a significant contraction on the right side.

The USGS collected real-time data at this site on 7-23-99. During this visit the stage was just past the peak and receding. A second visit was made on 7-25-99. By this time the stage had fallen to within the top banks. A low-flow visit was completed on 8-10-99.

DescElevREf:
RP1 - U/S bridge, top of concrete wall above 1st drain (Elev = 902.63)
RP2 - D/S bridge, top of concrete wall @ marked RM (Elev = 906.96)


BM #389 - Set nail and washer in north side of 18" oak, 237' south of station 172+72 
          (Elev = 902.93) from bridge plans


USGS Gaging Station located approximately 2300' upstream of bridge:

  Datum of stream gage is 868.26 ft above sea level, datum of 1929.
  The outside reference gage is a 6" wide channel iron with staff sections located 
  15' streamward of gage.

  RM 14 - 1/2" bolt on dowstream side of gage house, 11 ft west of river.
          (Elev=12.414 ft)
  RM 16 - USGS monument set in concrete 3' west of gaging station (Elev = 9.693 ft)
  RP 2 - Middle of float hole opening on angle iron in well (Elev = 6.61 ft)
  RP 3 - Top of nail located in upper staff plate backing (Elev = 10.294 ft)
  RP 4 - Top of nail located in lower staff plate backing (Elev = 3.216 ft)


SiteName:
Highway 25 over Minnesota River at Belle Plaine, MN

Description:
The study site is located on the Minnesota River .7 miles north of the town of Belle Plaine on State Highway 25.  The site is approximately 7.5 miles upstream from the USGS gaging station near Jordan (05330000) and 12 miles downstream from the USGS gaging station at Henderson (33032001).  The period of record for the Jordan station is from October 1935 to the current year, with an annual mean flow of 4425 cfs, and an instantaneous peak flow of 117,000 cfs recorded on April 11, 1965.  The USGS measured a discharge of 73,200 cfs and significant abutment and contraction scour at the site during real-time bridge scour measurments during the flood in April of 2001. 

The structure number for this site is 5260.  The Minnesota Dept of Transportation (MnDOT) built the current bridge in 1934.  The channel bottom at the time of construction was at approx. the same elevation as the top of footings (elev 695'). 
Eventually, the channel was scoured well below the footing bottoms, requiring restablization of the channel bed around the piers and left abutment with rip-rap due to a flood in April of 1951 that caused extinsive scouring of the channel. An underwater inspection was completed in 1991and 2000.  The 2000 inspection report contained upstream and downstream bridge face profiles which reflected streambed elevations had been returned to levels similar to the initial construction conditions.  Both inspections revealed the piers to be in generally good structural condition.  Debris buildup at the piers appears to be a recurring problem, especially at pier 1.

Structure #5260 is a metal truss bridge consisting of 3-150' continuous I-beam spans supported by two concrete column piers with partial web walls, and vertical abutments with wingwalls. The piers and the abutments are founded on piling; the pier piling is driven to an elevation of 637 - 667 ft, and the abutment piling is driven to an elevation of 665-670 ft.  Both abutments are set back about 30-40 feet from the top of the channel banks.  

Several measurements of scour have occurred at this site, by MnDOT and Collins Engineers, Inc.  Collins Engineers, Inc. preformed a series of investigations on the highway 25 bridge in the mid to late 1990's and found the bridge to be in good condition with minor scour depressions at the upstream end of pier #2.
 
The USGS revisited the site in October 2001 to conduct a post-flood survey and noted that both abutments had been re-stablized and lined with riprap as a result of the damage induced by the April 2001 flood.

DescElevREf:
The water-surface elevation was measured from the left upstream (north) abutment corner via a tapedown.  The elevation of the tapedown location was determined by inspection of the bridge plans to be 736.96 feet above sea level.  The surveyed water-surface elevations were also based on the elevation of the north abutment corner, 736.96 ft.


SiteName:
I-90 over Gallatin River near Manhattan, MT

Description:
The bridge site is located 4 miles southeast of Manhattan, Montana over the Gallatin River and is part of the I-90 Interstate highway.  I-90 crosses the Gallatin River via parrallel bridges, one for eastbound (upstream bridge) and the other for westbound traffic (downstream bridge).  Both bridges have two traffic lanes with a space approximately two lanes wide seperating the eastbound and westbound bridges.  A USGS gaging station (06043500) is located upstream of the site near Gallatin Gateway providing contiuous discharge data from 1984 to present and annual peak discharge data for 60 years (1889-Present).  Diversions for irrigation are common along the Gallatin River in the vicinity of the site. The data from the gage, along with drainage-area-adjustments resulted in flood-frequency estimates for the 100- and 500-year peak discharges at the bridge.  Q100 = 12,000 cfs and Q500 = 14,100 cfs at the bridge. 

Depending upon the year, the river is either highly anabranched or braided as it approaches the bridge and flow splits around a large flood bar immediately upstream of the I-90 crossing.   The bed material is very mobile, and can be compared to mounds of ball bearings.  The streambed configuration is highly variable from year to year.  Between measurements made on 5/22/97 and 6/18/97 at the bridge, the measured pier scour hole completely moved from pier 1 to pier 2.  A guide bank was installed on the right bank in the early 1990's in response to erosion that was encroaching upon the highway embankment.  The guide bank eliminated contraction of the river approximately one bridge width upstream of I-90, but 4-5 bridge widths upstream the river braids out considerably and an obvious contration at the bridge opening is observed.

A level 2 scour analysis was conducted on the site using the WSPRO computer model.  The model was used to conduct step-backwater calculations for the 100-year and 500-year peak discharges at the bridge.  The 100-year discharge passed through the bridge as free-surface flow without any overtopping of the roadway but approx. 5% (600 cfs) overtopping an embankment on the left bank, just upstream of the bridge.  Upon analysis of the 500-year discharge,  it was determined that unsubmerged pressure flow conditions would be used in the scour assessment and that 12% of the flow (1,692 cfs) overtopped the same embankment on the left bank, just upstream of the bridge.

The results of the WSPRO hydraulic characteristics are summarized below:

WSPRO Hydraulic Results:

Uncontracted Section  100-yr       
Average Velocity = 6.28 ft/s  Depth = 6.26     
Main Channel K = 182446   Left K = 0   Rigth K = 0

Bridge Section 100-yr           
Worst Case K-tube velocity = 10.86 ft/s  area = 52.5 sq. ft.

Uncontracted Section 500-yr
Average velocity = 5.22 ft/s  Depth = 8.08 ft
Main Channel K=281153   Left K=0  Right K=0

Bridge Section 500-yr
Worst Case K-tube = 10.49 ft/s  area = 59.1 sq ft

DescElevREf:
RM #1 is a chiseled "x" in the left upstream concrete abutment set equal to elevation 4305.48 (NGVD 1929).


Description:
The site is located approximately 6 miles south of Belt, MT on highway 89, adjacent to a roadside rest area.  Big Otter Creek joins Belt Creek about 1/2 mile upstream of the bridge.  A series of channels and high water marks are evident on the left bank, upstream of the bridge.  The flow contracts from the left bank, approximately 75 feet upstream of the bridge.  The large scour hole around pier 1 is from the 1981 flood that raveged most of the state.  Inspection of the bed material in the pier scour hole revealed an absence of finer material suggested that the site was subject to clear-water scour.  The downstream exit section appears to be re-establishing the edge of the main channel that was present prior to the 1981 flood through the presence of a vegetated berm directly downstream of pier #2.

DescElevREf:
RM #1 is a chiseled "x" in the left upstream concrete abutment set equal to elevation 99.99 ft.


SiteName:
Conehoma Creek at State Highway 35, near Kosciusko, Mississippi

Description:
The State Highway 35 crossing of Conehoma Creek consists of a 120-foot-long bridge near station 1642+58 (Bridge No. 153.1) with a span arrangement of 2 spans at 20 ft (feet), 1 span at 40 ft, and 2 spans at 20 ft. The bridge has 2 intermediate single-pile bents (nos. 2 & 5) and 2 intermediate double-pile bents (nos. 3 & 4). Both abutments are partially riprapped. Construction of the bridge was completed in 1941. 

The drainage area at the site is about 10.3 mi2 (square miles). The length of the channel from the site to the basin divide is about 6.0 mi (miles) and the average slope of the channel between points located at 10 and 85 percent of the length is about 17 ft/mi (feet per mile). Average channel and valley slopes in the vicinity of the crossing are about 5.4 ft/mi. The highway alignment is near normal to the channel and the flood plain in the vicinity of the crossing. Conehoma Creek converges with Yockanookany River about 2 ½ mi downstream of the State Highway 35 crossing (fig. 1). 

The floods of April 12, 1979, and April 5, 2001, were significant at this site. The 1979 and 2001 flood hydraulics and scour estimates are presented in this report. The estimated peak discharges for both of these floods were greater than the 100-year flood estimated using procedures outlined in the 1991 USGS report, "Flood Characteristics of Mississippi Streams."

The USGS recovered flood marks on May 9, 1979, along the upstream and downstream sides of the highway following the extreme flood of April 12, 1979. A bridge cross section, an approach cross section, and the flood marks were surveyed and photographs were taken by a private contractor in June 1979. The flood crested at an elevation of 402.6 ft at the downstream side of the bridge. The cross section surveyed at the downstream side of the bridge in June 1979 indicates scour occurred at the bridge during the flood. The scour likely occurred as the flood was peaking and perhaps beginning to recede. 

The MDOT obtained photographs and ground-to-grade information at the site on April 9, 2001, after the severe flooding that occurred on April 5. The USGS flagged flood marks along the upstream and downstream sides of the highway on April 9, 2001, and surveyed these marks and additional channel geometry on February 13, 2002.  The bridge section was surveyed during the site visit on October 27, 1994, for a scour evaluation report provided to the MDOT on February 10, 1995. When the 1979 and 1994 bridge sections were compared, it was apparent that some repairs (probably consisting of some earthwork and riprap) had been made, but no details were available at the time of this report. The flood crested at an elevation of 401.7 ft at the downstream side of the bridge. The cross sections surveyed at the downstream side of the bridge in April 2001 and February 2002 indicate scour occurred at the bridge during the flood.

Bed samples collected by the USGS on October 27, 1994, indicated the channel material was fine sand with a D84 of 0.29 mm, D50 of 0.10 mm, D16 of 0.017 mm, and a gradation coefficient of about 4.1. Based on MDOT geotechnical reports in the area, the stream has very likely scoured down into or near the top of the Zilpha Clay formation during the floods of April 12, 1979, and the April 5, 2001. A 1997 MDOT geotechnical report for Yockanookany River at proposed State Highway 14 Bypass of Kosciusko, located about 1.9 mi northwest of this site, indicates that the top of the Zilpha formation possesses a cohesion of about 1,320 lb/ft3, a friction angle of 31 degrees, and a unit weight of 119 lb/ft3. Gradation tests suggest that the top of the formation has a D84 of about 0.37 mm, D50 of 0.16 mm, D16 of 0.026 mm, and a gradation coefficient of about 3.8. The 1941 test-pile reports at this site noted that soil borings indicated sand stone at elevation 377.0 ft, and indicated a significant increase in bearing capacity at about the same elevation. So, the top of the Zilpha formation is likely at about elevation 377 ft at this site.

DescElevREf:
Elevations presented are to MDOT Datum from the bridge plans, which appears to be National Geodetic Vertical Datum of 1929 at this site.


Description:
The Knik River is located approximately 35 miles northeast of Anchorage near the town of Palmer. The river emanates from the Knik Glacier approximately 17 miles upstream from the bridges and drains into Knik Arm, the northern most extent of Cook Inlet, approximately 8 miles downstream of the bridge. At the mouth of the glacier, the river is anastomosing, but reduces to a single strand through the bridge reach. Branching of the channel resumes downstream of the bridge, but not to the extent found in the headwaters. 

A daily station (station 15281000) was operational at this site from 1958-1988 , 1991-1992, and was reactivated in 2001. The gage is located at the new bridge on the right bank. Average annual mean flow (from 1960-1987) is 6904 cfs, with annual peaks occurring in August-September and averaging 37,000 cfs (excluding outburst floods). High volume (up to 359,000 cfs) glacial outburst floods occurred annually on the Knik River up until 1966. Due to recession of the Knik glacier these flows no longer occur.

Two bridges are located in the study reach (figure 2). The upstream bridge was built to accommodate the high volume outburst floods and extends across the entire channel. The newer downstream bridge was built after the cessation of the outburst floods and its approaches constrict the flow. The embankments for the new bridge are rip rapped and spur dikes extend upstream beyond the old bridge, which is discussed in the database under Site ID #2.   

The right overbank is wide, level, unvegetated, and armored with gravel and cobbles. The left overbank rises steeply from the river and is densely vegetated.

A survey of the Knik River and the new bridge was conducted in 1999 for the purpose of conducting a level 2 bridge scour anaylsis.  A HEC-RAS model of the site was developed and used in conjunction with HEC-18 procedures to predict the scour attributed to the contracted bridge opening.

DescElevREf:
A gage (station 15281000) was operational at this site from 1958-1988 and from 1991-1992. Gage datum is tied to a Corps of Engineers benchmark (elevation 62.67 ft above MSL) on the upstream side of the left abutment of the old bridge. Elevation to gage datum for this point is 32.50 ft. To correct elevations to gage datum adjust by 30.17 ft.


SiteName:
Galvin Road Overflow Bridge for the Chehalis River near Centralia, WA

Description:
The Galvin Road Overflow bridge is approximately 2.5 miles northwest of the town of Centralia, WA and serves as a relief opening on the east floodplain of the Chehalis River during high-flow events (figure 1).  The current bridge at the site is 382 feet (ft) long and consists of 10 spans supported on 11 piers.  A low spot in the embankment fill 500 ft east of the bridge overtops during major floods and prevents pressure flow at the overflow bridge.   The main channel of the Chehalis River is 1200 ft west of the Overflow bridge and is spanned by a 400 ft concrete bridge.  The main bridge, Overflow bridge, and low spot in the fill are the only places where flood flows can pass to downstream of Galvin Road.  The bridge was damaged on February 9, 1996, when the Chehalis River experienced a major flood.  The flood produced a massive scour hole under the western one-third of the bridge and undermined the timber piles of one intermediate pier, which caused the bridge deck to sag 18 inches.  A USGS gaging station (12027500) on the Chehalis River at Grand Mound has been operational four miles downstream of the Galvin Road Overflow bridge from 1929 - 2002.  

The Chehalis River is a fine- to medium-grained sand channel with a wide floodplain in the vicinity of the Galvin Road overflow bridge.  The Galvin site is more complicated than most other bridge sites in the area because of a wide flood plain, upstream overbank flow diversion, off-channel storage and backwater effects from the downstream reaches of the Chehalis River.  The backwater effects stems from an adverse channel gradient in the vicinity of the bridge crossing.  Rather than a uniformly sloping channel in the downstream direction, the main channel of the Chehalis River between river miles 61.7 and 62.9 (the Galvin Road bridge is located at river mile 64.08) has an adverse slope of .0005 ft/ft.  The adverse slope of the channel in the vicinity of Galvin Road is attributed to an abrupt narrowing (pinch) of the Chehalis River valley topography approximately 3.5 river miles downstream of the Galvin Road crossing.  The severe pinch in the river valley creates backwater during high flow events and leads to frequent flooding of Centralia and Interstate 5.  Under most hydraulic conditions, the backwater created by the downstream adverse channel slope is just as or more severe than the backwater caused by the Galvin Road overflow bridge contraction.  

Three hydraulic reports involving the Galvin Road Overflow bridge were developed prior to the 1996 flood: 1) FEMA Flood Insurance Study Report for Unincorporated Lewis County (FEMA, 1991); 2) Galvin Road Overflow Bridge Hydraulics Study dated November 1986 by Robert E. Meyer Consultants (REM 1986); 3) a second Galvin Road Overflow Bridge Hydraulics Study dated October 1991, also by REM (1991).  The purpose of the November 1986 study was to provide Lewis County with the hydraulic information necessary to select a replacement design for the Galvin Road Overflow bridge.  Due to the bridge being within FEMA’s regulatory floodway, a hydraulic study had to be completed to show that the new bridge would not increase the 100-yr flood water surface elevation.  REM developed a HEC-2 model of the Chehalis River and used it to show that with minor channel bed excavation, the overflow bridge could be shortened from 530 ft to about 360 ft and still meet FEMA’s requirements.  In 1991, a 382 ft long bridge was selected and REM completed a second study, which showed that the proposed bridge satisfied FEMA’s no increase requirement (Northwest Hydraulic Consultants 1996).  

The REM studies were restricted to satisfying FEMA’s no increase requirement, and did not give a realistic picture of the hydraulic conditions that could develop during major flood, and did not accurately address scour as a potential problem at the site.  A review of the HEC-2 input and output by Northwest Hydraulic Consultants prior to the 1996 flood revealed several problems.  The major problem involved the use of non-representative Manning’s n roughness coefficients in the vicinity of the bridge.  The REM model used an n value of 0.015 for the main channel of the Chehalis River and 0.104 for the Overflow bridge opening.  The n value is too low in the main channel and too high for the overflow waterway; reasonable values for both model sections range from 0.03 - 0.05.  This, along with other problems in the model, caused the model to significantly underestimate the flow through the Overflow bridge.  The REM output indicated that for the FEMA 100-yr flood (56,000 cubic feet per second (cfs)), less than 3,800 cfs was conveyed through the overflow and average velocities were less than 1 foot per second (fps).  A simplified HEC-2 model of the site was developed by Northwest Hydraulic Consultants using surveyed high-water marks and cross-sections from the 1996 flood.  The model developed from field data showed that 25,000 to 30,000 cfs passed under the overflow bridge with average velocities ranging from 8 to 10 fps.

The hydrologic event responsible for the 1996 flood was an intense winter storm that hit southwestern Washington.  The peak discharge that was measured during the 1996 flood was approximately 74,900 cfs on February 9.  Northwest Hydraulic Consultants conducted a flood frequency analysis on the historical data (1929-1996) from the Grand Mound gaging station.  Estimates of the 100- and 500-year discharges are 73,600 cfs and 99,800 cfs, respectively.  The existing FEMA flood insurance study lists the 100-yr and 500-yr discharges as 56,000 cfs and 70,000 cfs; however these were based upon a shorter period of record (1929-1976).  From surveyed high-water marks of the February 9, 1996 flood, it appears that 45,000 to 50,000 cfs remained in the Chehalis River main channel and 25,000 to 30,000 cfs passed through the Overflow bridge.  As the floodplain flow approached the new Overflow bridge, the new western approach fill significantly blocked the flow and intensified the contraction and velocities at the left (western) portion of the Overflow bridge

DescElevREf:
The elevations reported were taken from the Galvin Road overflow bridge plans.


SiteName:
SR 370 over Bitterroot River at Bell Crossing near Victor, MT

Description:
The Bell Crossing bridge over the Bitterroot River is part of a roadway that connects the East Side highway with US 93.  Due to the expansivness of the Bitterroot river floodplain in the vicinity of the Bell Crossing bridge, there are many relief structures along the connector roadway that assist in conveying high-flow events.  A USGS gaging station is located at Bell Crossing (12350250) and has provided seasonal records since 1987.  Discharge measurments are made from July through September to help regulate to intense irrigation pressure from the surronding farmlands during the late summer.  Water from the Bitterroot river is diverted upstream of the bridge for irrigation of about 80,000 acres.  The Painted Rocks Lake (station number 12342000) provides some regulation at the site.  At high stages, the left bank overflows and the channel becomes braided with trees and vegetation creating some amount of backwater.  The right bank above and below the bridge is riprapped and will overflow at extremely high stages.  Bypass flow will occur through 8 ft wide culverts located 500 ft from both ends of the bridge and through a bridge opening 1/2 mile to the east of the site.  The nature of the streambed in the vicinity of the site is highly unstable also prone to a large volume of debris.

The Bell Crossing is a 4 span bridge having three, 4.5 ft wide sharp-nosed, webbed  piers.

No real-time measurements were made on the upstream side of the bridge or the approach section during the flood event.  A level 2 scour analysis was however, conducted on the site using the WSPRO computer model.  The model was used to conduct a step-backwater calculations for the 100-year and 500-year peak discharges at the bridge.  The 100-year discharge passed through the bridge as free-surface flow without any overtopping of the roadway.  Upon analysis of the 500-year discharge,  it was determined that unsubmerged pressure flow conditions would be used in the scour assessment.  The scour results are probably conservative and overstate the hydraulic conditions for the 500-year discharge because of the relief that the bridge would likely receive from nearby overflow structures.     

WSPRO Hydraulic Results:

Uncontracted Section  100-yr       
Average Velocity = 3.96 ft/s  Depth = 8.51      
Main Channel K = 593320   Left K = 46136   Rigth K = 138971 

Bridge Section 100-yr           
Worst Case K-tube velocity = 8.82  area = 141.7 sq. ft.

Uncontracted Section 500-yr
Average velocity = 4.20 ft/s  Depth = 10.37 ft
Main Channel K=824755   Left K=78353   Right K=235360

Bridge Section 500-yr
Worst Case K-tube = 9.24  area = 183.9 sq ft

DescElevREf:
The elevation of the gage is 3330 ft above sea level; this value was determined from a topographic map rather than directly surveyed.

RM #1 - standard brass cap set in right downstream bridge wingwall 50ft upstream from gage house. 
              Elevation is 21.51 ft above gage datum.
RM#2 - is the head of lag screw in a power pole 9ft upstream and 9ft shoreward from gage house.
             Elevation is 12.85 ft above gage datum.
RM#3 - is the head of a lag screw in pine tree 50 ft downstream from gage house.  
             Elevation is 11.79 ft above gage datum.
RP - is a yellow paint mark on the streamward end of a flat boulder, 15ft streamward from the gage house.
       Elevation is 10.43 ft above gage datum.


SiteName:
US 2 over Beaver Creek Overflow 9 Miles West of Saco. MT

Description:
The overflow bridge 9 miles west of Saco, is one of three openings that convey water of Beaver Creek through US Highway 2 during high-runoff periods.  This site is located on the left overbank floodplain of Beaver Creek, which flows northeast out of the Little Rocky Mountains in the Highline Country of Montana.  No clearly-defined main channel exists and the floodplain consists of densely-vegetated erosion resistant pasture and rangeland.  No peak-discharge data are available at the bridge site, but indirect measurements on Beaver Creek indicated that the magnitude of the September 1986 flood was approximately a 100-year return period event.  High water marks surveyed after the 1986 flood suggest that the peak stage at the bridge was 92.89 ft.  Inspection of the surronding area and a lack of evidence of additional scour following the 1986 flood, the floodplain is presumed to be stable and clear-water scour is likely to occur at the bridge. 

The magitude of the 100- and 500-year floods for Beaver Creek are 13,500 and 20,700 cfs, respectively.  Step-backwater calculations (WSPRO) at the bridge for the 100-year discharge indicated that the overflow bridge 9 miles west of Saco would carry 16% of the total Beaver Creek discharge (2,180 cfs) as free-surface flow.  For discharges greater than the 100-year flood, step-backwater calculations showed that the road would be overtopped east of the bridge. For the 500-year flood, it was estimated that the road overflow would carry approximately 3,960 cfs and the bridge would carry the same percentage of the flow for the remainder of the 500-year flood (2,680 cfs).  A level 2 scour analysis was conducted on the site using the WSPRO computer model and the 100- and 500-year discharges.
The results of the WSPRO hydraulic characteristics are summarized below:

WSPRO Hydraulic Results:

Uncontracted Section  100-yr       
Average Velocity = .49 ft/s  Depth = 3.95      
Main Channel K = 369110   Left K = 0   Rigth K = 0

Bridge Section 100-yr           
Worst Case K-tube velocity = 6.95  area = 15.7 sq. ft.

Uncontracted Section 500-yr
Average velocity = .46 ft/s  Depth = 5.2 ft
Main Channel K=582823   Left K=0  Right K=0

Bridge Section 500-yr
Worst Case K-tube = 5.9  area = 22.7 sq ft

DescElevREf:
The datum for the surveys is an RM#3 (chiseled X) located on the left upstream concrete abutment.  The local datum elevation of RM#3 = 96.15 ft.


SiteName:
SR 37 over James River near Mitchell, SD

Description:
The study site is located on the James River 20 miles north of the town of Mitchell on State Highway 37.  The site is approximately 4.5 miles downstream from the USGS gaging station near Forestburg (06477000).  High flow measurements for the Forestburg gaging station are actually made from the SR 37 bridge therefore a wire weight is installed on the upstream side of the bridge. The period of record for the station is from March 1920 to the current year, with an annual mean flow of 493 cfs, and an instantaneous peak flow of 25,600 cfs recorded on April 6, 1997.  The SD USGS measured 17,100 cfs during the flood of April 2001 during which real-time bridge scour measurements were made at the site by the USGS National Bridge Scour Team.  A manned boat was deployed during the April 2001 flood and detailed scour data was collected with a 1200 kHz ADCP

The site is located in a highly rural/agriculatural landscape with moderate topographic relief.  The was no roadovertopping nor any relief bridges associated with the SR 37 bridge, therefore all of the flow in the James River contracted and passed through the bridge opening.  The bridge is a concrete girder, three span structure supported by two groups of cylindrical piers (3 in each group) which are both founded on steel piles.  The upper 10-15' of the bed is comprised of a sandy-silt followed by 10-20 ft of silty-clay.

Some of the information (slope in vicinity and drainage area) found in the stream data tab were taken from the description of the Forestburg gaging station and applied to the SR37 bridge due to its close proximity and similar basin characteristics.

DescElevREf:
The datum of the site is 1208.34 ft above sea level, and the check bar elevation is 37.849 ft.


SiteName:
247 Street over James River near Mitchell, SD

Description:
The study site is located on the James River approximatley 6 miles north of the town of Mitchell and east of State Highway 37 on 247 street.  The site is approximately 21 miles downstream from the USGS gaging station near Forestburg (06477000).  The USGS National Bridge Scour Team was deployed to the site to collect real-time bridge scour measurments during the flood in April of 2001.  Boat access at the site was unavaliable therefore all scour measurements were collected from the bridge deck.  247 street and the bridge were closed at the time of the measurements due to overtopping of the roadway on the left floodplain.  

The site is located in a highly rural/agriculatural landscape with very little topographic relief, especially in the left floodplain.  The bridge is a concrete girder, three span structure supported by two groups of cylindrical piers (2 in each group) which are both founded on timber piles.  The channel bed is comprised of a silty-clay with a narrow horizontal clay wedge.  The James River has a great deal of meander in the vicinty of the bridge.  The left floodplain is expansive at the bridge and the right overbank consists of bluffs rising relatively steeply from the edge of channel.

DescElevREf:
The water-surface elevation was measured from the both the upstream (north) and downstream (south) edges of the bridge via a tapedown at rail #15.  The elevation of the tapedown location was surveyed to be 1236.29 feet above sea level.  The surveyed water-surface elevations were based on the elevation of the top of pavement at the right downstream abutment corner, 1230.78 ft.


SiteName:
US 93 over Bitterroot River near Darby, MT

Description:
The US 93 bridge over the Bitterroot River is a USGS gaging station site that has been in continuous operation since 1939 and located 4.1 miles southeast of Darby in southwestern Montana.  A cable way is located between 50-100 feet upstream of the bridge.  The bridge is highly skewed, therefore the distance to the cable way is about 100 feet on the left bank and approximately 50 feet on the right bank.  The site is slightly regulated by Painted Rocks Lake (station number 12342000) located upstream along the West Fork of the Bitterroot River.  The river is essential for irregation in the region.  Diversions irrigate approximately 5000 acres of land upstream and about 500 acres immediately downstream of the site.  The river bed is comprised of coarse material (mostly cobbles), having a D50 on the order of 50 mm.  The channel is void of vegetation, and overbanks are lined with mostly desciduous trees and some shrubbery.  

US 93 bridge is supported by one webbed pier (center of bridge) and two piers consisting of 6 separate cylindrical piles located on the abutments.  The bridge spans the channel under low-flow conditions, with the center pier located along the right edge of water.  The flow splits around a small island approximately 250 feet upstream of the bridge under both low- and high-flow conditions.  Large debris piles have been witnessed to accumulate on the center peir during high-flow periods.

DescElevREf:
The datum of the gage is 3,942.14 feet above sea level.  

RM #4 - is top of steel fence post, painted yellow, in fence line 29 ft shoreward and 10 ft upstream from gage.      
            Elevation is 13.71 ft above datum, and 3,955.85 ft above sea level.
RM #5 - is top of yellow painted anchor bolt on downstream side of left bank A-frame pedestal.
            Elevation is 14.22 ft above datum, and 3,956.36 ft above sea level.
RM #6 - is top of lag bolt in power pole 50 ft shoreward and 10 ft upstream at end of fence line.
            Elevation is 17 ft above gage datum, and 3,959.00 ft above sea leve.


SiteName:
US 2 over Beaver Creek Overflow 7 Miles West of Saco. MT

Description:
The overflow bridge 7 miles west of Saco, is one of three openings that convey water of Beaver Creek through US Highway 2 during high-runoff periods.  This site is located on the left overbank floodplain of Beaver Creek, which flows northeast out of the Little Rocky Mountains in the Highline Country of Montana.  No clearly-defined main channel exists  and the floodplain consists of densely-vegetated erosion resistant pasture and rangeland.  No peak-discharge data are available at the bridge site, but indirect measurements on Beaver Creek indicated that the magnitude of the September 1986 flood was approximately a 100-year return period event.  High water marks surveyed after the 1986 flood suggest that the peak stage at the bridge was 92.35 ft.  Inspection of the surronding area and a lack of evidence of additional scour following the 1986 flood, the floodplain is presumed to be stable and clear-water scour is likely to occur at the bridge. 

The magitude of the 100- and 500-year floods for Beaver Creek are 13,500 and 20,700 cfs, respectively.  Step-backwater calculations (WSPRO) at the bridge for the 100-year discharge indicated that the overflow bridge 7 miles west of Saco would carry 34% of the total Beaver Creek discharge (4,570 cfs) as unsubmerged pressure flow.  For discharges greater than the 100-year flood, step-backwater calculations showed that the road would be overtopped near the bridge, and it was estimated the the bridge would carry the same percentage of the flow for the 500-year flood (5,690 cfs).  A level 2 scour analysis was conducted on the site using the WSPRO computer model and the 100- and 500-year discharges.
The results of the WSPRO hydraulic characteristics are summarized below:

WSPRO Hydraulic Results:

Uncontracted Section  100-yr       
Average Velocity = .75 ft/s  Depth = 5.24      
Main Channel K = 607596   Left K = 0   Rigth K = 0

Bridge Section 100-yr           
Worst Case K-tube velocity = 8.26  area = 27.7 sq. ft.

Uncontracted Section 500-yr
Average velocity = .77 ft/s  Depth = 6.33 ft
Main Channel K=833666   Left K=0  Right K=0

Bridge Section 500-yr
Worst Case K-tube = 10.29  area = 27.7 sq ft

DescElevREf:
The datum for the surveys is an RM#2 (chiseled X) located on the left upstream concrete abutment.  The local datum elevation of RM#2 = 94.40 ft.


